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In order to clarify the genetic differentiation and reproductive traits of mixed polyploid populations in Parasenecio kamtschaticus complex, geographical distribution, genetic diversity, and reproductive performance were compared among three intraspecific types composed of two cytotypes and two varieties in Japan. Diploid P. kamtschaticus var. kamtschaticus (2×-kamtschaticus) was distributed at the center of the distribution range, tetraploid P. kamtschaticus var. kamtschaticus (4×-kamtschaticus) existed widely throughout the entire range, and tetraploid P. kamtschaticus var. bulbifera (4×-bulbifera), producing bulbils, was restricted to higher elevations. Genetic structure was analyzed using allozyme markers. The genetic diversity of 4×-kamtschaticus was higher than that of 2×-kamtschaticus, with that of 4×-bulbifera being intermediate. Populations of 4×-bulbifera and 2×-kamtschaticus were genetically discriminable from each other in principle coordinate analysis, and the genetic structure of 4×-kamtschaticus populations largely overlapped with those of the other types. Flower and achene production levels were highest in the 4×-kamtschaticus populations and lowest in the 4×-bulbifera populations. Germination activity of achenes was highest in the 2×-kamtschaticus populations and lowest in the 4×-bulbifera populations. Fruit-set success of 4×-bulbifera decreased with elevation because of a shorter growing season, indicating the importance of vegetative reproduction by bulbils at higher elevations. Unexpectedly, the inbreeding coefficients of the 4×-bulbifera populations were the lowest among the three types. Occasional achene production by outcrossing might maintain the high genetic diversity of the 4×-bulbifera populations. The evolution of polyploidy and subsequent bulbil production might enable P. kamtschaticus to disperse a wider range of environmental conditions. [ABSTRACT FROM AUTHOR]

Pollinator taxa may vary in their contribution to plant outcrossing rates and hence differ in their influence on plant fitness. In plants that have ornithophilous floral traits (large, deep-tubed orange-red flowers with dilute nectar), it is expected that birds should be the most effective agents of outcrossing. However, bees often pollinate plants with ornithophilous floral traits and may contribute to their outcrossing. To assess the contribution of bees to outcrossing rates and inbreeding in the rare self-compatible treelet Aloe thraskii, we compared outcrossing rates (t) and adult inbreeding coefficients (F), in bird-excluded and open-pollinated plants. We then tested whether outcrossing rates, and inbreeding depression (δ) estimated using Ritland’s genetic marker-based approach, varied according to bee and bird visitation rates, plant height, flowering population size, population density, and isolation distance across eight populations. Outcrossing rates did not differ between progeny from open-pollinated and bird-excluded inflorescences. Outcrossing rates increased with bee visitation, but not bird visitation. Adult inbreeding coefficients were low (F = 0–0.1), and inbreeding depression estimates were high (δ = 0.59–1). Estimates of inbreeding depression did not vary according to population aggregation. These results highlight the contribution to outcrossing that insect pollinators can make to outcrossing rates of rare plant species that are seemingly adapted for bird pollination. [ABSTRACT FROM AUTHOR]

We used allozymes to investigate the structure of genetic variation in populations of the perennial herb Silene nutans at local (Denmark), regional (Nordic area) and wide (over a 19° latitudinal gradient) geographic scales in north-western Europe. New data from Denmark were combined with data from previously studied Fennoscandian and western populations. We related patterns of nuclear variation for 26 Fennoscandian and western populations to the phylogeographic patterns revealed by four plastid (chloroplast) DNA markers. Levels of genetic diversity were similar within Denmark and Sweden/N Finland. Compared to Sweden/N Finland, the Danish populations show lower and nonsignificant F values. The genetic structure reveals no grouping of the Danish populations according to their geographic origin (Jutland-Zealand). Within Nordic populations (from Denmark, Sweden and N Finland), there is a weak geographic pattern of allozyme differentiation. The high latitude populations are genetically depauperate compared with populations from Western Europe. At the whole north-western European scale, the structure of allozyme variation within S. nutans shows geographic differentiation (Nordic versus western populations), and some congruence with plastid phylogeographic patterns. A high level of allozyme genetic differentiation is found between Nordic and western populations (8.0 %), but also between populations within haplotype categories (19.4 %). The overall geographic structure of allozyme variation of S. nutans appears to be primarily a reflection of past (postglacial) migration history, whereas more recent adaptive and stochastic processes have occurred at more local scales. [ABSTRACT FROM AUTHOR]

Genetic data could be considered irrelevant to the conservation of species in imminent danger, and that habitat protection and ex situ conservation strategies should be carried out regardless of the existence of estimates of genetic diversity. However, genetic data are needed to determine the current state of diversity of the species, the genetic structure and the genetic differentiation between populations and therefore to establish the most suitable management strategy. We compared genetic diversity and differentiation estimated from allozymes and random amplified polymorphic DNA (RAPD) in the three known natural populations of the critically endangered endemism from the Island of Tenerife (Canary Islands) Helianthemum juliae Wildpret. There were discrepancies in levels and structuring of genetic diversity measured with both molecular markers due to genome sampling. So, whereas allozymes allele frequency revealed a low genetic differentiation between natural populations ( F = 0.034), the presence/absence of RAPD data matrix showed a considerable level of genetic differentiation ( F = 0.397) between these populations. Genetic data identify 20 unique genotypes distributed within H. juliae populations, which supposes an important finding for conservation management of this endangered species. Considering that the three populations showed unique genotypes, management strategies should be focused on strengthening these genotypes in the whole of the species. So, although considerable genetic differentiation has been detected between the natural populations, bearing in mind the high extinction probabilities described for the species, genetic data would support the establishing of new localities with individuals from different natural populations in a conservation genetics strategy. [ABSTRACT FROM AUTHOR]

The main Korean mountain range that stretches from north to south (the Baekdudaegan) has been suggested to harbor an important glacial refugium for boreal and temperate plant species. Under this scenario, we expect high levels of within-population genetic variation and low or moderate degree of among-population differentiation within these species. To test this hypothesis, we examined clonal diversity and levels of allozyme diversity in the boreal Iris odaesanensis and in its temperate congener Iris rossii. In addition, we compiled data on boreal and temperate species whose distribution in the Korean Peninsula is mostly centered in the Baekdudaegan to determine if there is a common pattern. We found lower clonal diversity in I. odaesanensis compared to I. rossii. Both studied species maintained high levels of genetic variation as well as a moderate genetic differentiation ( %P = 52.5 and 47.5, A = 1.70 and 1.58, H = 0.158 and 0.150, and F = 0.196 and 0.189 for I. odaesanensis and I. rossii, respectively), in line with what occurs for the species distributed on the Baekdudaegan ( n = 14, %P = 46.7, A = 1.73, H = 0.161, and F = 0.190). This study strongly suggests that the Baekdudaegan may have acted as a refugium for boreal and temperate species, in a similar way to the southern Appalachians in the eastern United States. [ABSTRACT FROM AUTHOR]

We used allozymes to elucidate the genetic variation of Pilosella echioides and P. rothiana in the Pannonian Basin and its relationship with morphology and modes of reproduction. The former species consists of sexual diploid, apomictic tetraploid, and very rare sexual tetraploid populations; the latter is exclusively tetraploid and apomictic. As expected, we detected the highest intra-population variation in diploid populations of P. echioides. Nonetheless, 73 % of populations of tetraploid P. echioides and 64 % of P. rothiana consisted of 2-7 multilocus allozyme genotypes, the means being 5.75 in P. echioides and 2.64 in P. rothiana. Both the proportion of distinguishable genotypes ( G/N) per population and genotype diversity ( D) per population significantly differed between diploid P. echioides (means 0.415 and 0.828, respectively) on the one hand and tetraploid P. echioides (means 0.252 and 0.387, respectively) and P. rothiana (means 0.213 and 0.347, respectively) on the other. Rather surprisingly, we found an excess of homozygotes (positive F) in diploids, which indicates inbreeding. Tetraploids of P. echioides have most likely originated from only a few polyploidization events and have spread thanks to agamospermy-at least populations from the NW part of the area under study seem to be monophyletic. Genetic differences within the putatively hybridogeneous species P. rothiana are small. It seems plausible that it has a common origin and that it spreads independently of its parents ( P. echioides and P. officinarum). A certain level of genetic diversity can be caused by residual sexuality or less likely by repeated polytopic hybridization between P. echioides and P. officinarum. Pilosella sterrochaetia is reported here from Hungary for the first time. It is an extremely rare primary diploid hybrid between diploid P. echioides and P. leucopsilon. Its intermediate nuclear genome size also confirms its hybrid origin. [ABSTRACT FROM AUTHOR]

The genetic diversity of four new species related to southwestern Sichuan buckwheats was examined using karyotypes, allozymes and intersimple sequence repeats (ISSR). Karyotype analysis showed that Fagopyrum wenchuanense, F. qiangcai and F. pugense are diploid (2 n = 2 x = 16) while F. crispatofolium is tetraploid (2 n = 4 x = 32). The karyotype evolutionary trend of buckwheat indicated that F. crispatofolium, F. gracilipes var . odontopterum and F. gracilipes seemed to be more advanced than F. wenchuanense, F. qiangcai, F. pugense, F. esculentum, F. cymosum and F. tataricumare. Three polymorphic enzyme systems were used for the examination of variation, including peroxidase, esterase and superoxide dismutase. Consistent banding patterns were obtained for esterase and superoxide dismutase, while peroxidase produced a large number of sharp bands. A total of 18 ISSR primers were selected for the analysis and showed high variations among the species. Allozymes and ISSR markers were utilized to estimate the genetic distance among accessions and to draw phylogenetic trees. Our data provide evidence of a high degree of genetic diversity among southwestern Sichuan buckwheats. In addition, both cultivars and wild types showed a high degree of divergence suggesting a complex domestication process in this crop. This study provides a better understanding of evolutionary mechanisms and genetic relationships in four new species of buckwheat. [ABSTRACT FROM AUTHOR]

Genetic differentiation in space can be detected at various scales. First, habitat fragmentation can produce a mosaic genetic structure. Second, life history aspects of a species such as dispersion, mating system, and pollination can generate a genetic structure at a finer level. The interplay of these levels has rarely been studied together. In order to assess the effects of forest fragmentation we analyzed the genetic structure at two spatial scales of the terrestrial orchid Cyclopogon luteoalbus, which lives in patches inside forest fragments in a cloud forest of eastern Mexico. We hypothesized high differentiation between forest fragments and strong spatial genetic structure within fragments under this scenario of strong fragmentation and restricted dispersal patterns. Using 11 allozymic loci we found high genetic diversity at fragment level with moderate differentiation among fragments, and at patch level, strong and variable spatial genetic structure among life cycle stages with high inbreeding coefficients. We also found bottlenecks indicating recent population size reductions. While both inbreeding and restricted seed dispersal may explain the strong spatial genetic structure at patch level, reduction in population size may explain the genetic structure at fragment level. However, the levels of genetic diversity indicate that some between-fragment gene flow has occurred. Bottlenecks and high inbreeding at patch level may result in local extinctions, but as long as an important number of fragments remain, patch recolonization through immigration is possible in C. luteoalbus. [ABSTRACT FROM AUTHOR]

In this work we assessed the genetic diversity of 32 C. calceolus populations from Poland. Mean genetic diversity was moderate ( P = 36.4%, A = 1.58, H = 0.143, F = 0.059), and seven geographic regions did not differ significantly in their levels of polymorphism ( p > 0.05), although allele frequencies varied greatly. Only four unique alleles were found, at three sites in southern and southeastern Poland. Genetic ( P, A) and genotypic diversity parameters ( G, G) were significantly correlated with population size ( p < 0.001). In the 32 studied populations we separated 422 different multilocus genotypes; none was common to all populations. Overall population differentiation was moderate at 0.137 ( p < 0.001), but we found a significant pattern of isolation by distance for the whole dataset ( r = 0.65, p < 0.001). Our chloroplast DNA (cpDNA) results suggest a single evolutionary lineage and a common origin for all Polish C. calceolus populations. Information about the genetic health of C. calceolus populations should be useful in developing conservation strategies. [ABSTRACT FROM AUTHOR]

Cattleya elongata is a rupicolous orchid species spread throughout and endemic to outcrop islands in campo rupestre vegetation of the Chapada Diamantina, northeastern Brazil. We scored nine natural populations of C. elongata for morphological and genetic variability, covering the whole distribution area of the species, using allozymes and ISSR markers and morphometric multivariate analyses. Genetic variability in allozimes was relatively high ( H = 0.12-0.25), and unexpectedly higher than the values based on ISSR ( H = 0.16-0.19). The populations present moderate structuring (allozymes, Φ = 0.14; ISSR, Φ = 0.18) and low inbreeding (allozymes, F = 0.06). Genetic similarity among the populations was high in both markers, in spite of the discontinuity of the outcrops of the Chapada Diamantina. We found no particular biogeographical pattern to the distribution of the genetic and morphologic similarity among the populations of C. elongata. We found high morphological variability with moderate differentiation among the populations. We did not find any correlation among genetic, morphological, and geographical distances, and among the variability found in the morphological and genetic markers. The differences observed between the two genetic markers and the various morphological markers examined here indicated that the isolated use of any single parameter of these different populations for conservation planning or management would not consider all of the variability to be found in the species, as found in other Brazilian campos rupestres plants. [ABSTRACT FROM AUTHOR]

lthough reticulation has indisputably played an important role in the evolutionary history of the genus Hieracium s. str. (Asteraceae), convincingly documented cases of recent interspecific hybridization are very rare. Here we report combined evidence on recent hybridization between two diploid species, Hieracium alpinum and H. transsilvanicum. The hybrid origin of the plants from the Romanian Eastern Carpathians was supported by additive patterns of nuclear ribosomal DNA polymorphism (ITS), an intermediate position of hybrid plants in principal coordinate analysis based on amplified fragment length polymorphism phenotypes (AFLP), and additivity at one allozyme locus. Flow cytometric analyses and chromosome counting showed that two hybrids were diploid (2n ~ 2x ~ 18) while one was surprisingly tetraploid (2n = 4x = 36). To our knowledge, this is the first record of spontaneous polyploidization following interspecific crossing in the genus. Allozyme data, especially the presence of unbalanced heterozygosity at one locus, suggest the origin of this tetraploid via a triploid bridge with subsequent backcrossing to H. alpinum. According to PCR-RFLP analyses of the trnT- trnL intergenic spacer, all H. × krasani hybrids examined had the H. alpinum haplotype while H. transsilvanicum served as a pollen donor. The hybrids occurred at the locality with abundant H. alpinum plants where paternal H. transsilvanicum was missing. Previously reported instances of interspecific hybridization between the same parental taxa showed an opposite direction of crossing and relative abundance of parental taxa. This suggests that the direction of hybridization might be influenced by the frequency of parental taxa at the locality. [ABSTRACT FROM AUTHOR]

Information from allozymes, ploidy levels, morphology, cross-compatibility and biogeography suggests that the easternmost occurrences of the Ponto-Caucasian Viola sieheana should be considered to belong to a separate species, V. caspia. Morphological characters delimitating V. sieheana and V. caspia are presented and discussed. The main distribution of V. sieheana s. str. is in the eastern Balkans, Turkey, Cyprus, and The Lebanon, and of V. caspia in the Caspio-Caucasian region westwards to Crimea and north-eastern Turkey. Their distributions in the intermediate areas remain unknown. Plants of V. sieheana s. str. from Cyprus, Greece, and Turkey were all blue-flowered and had the chromosome number 2 n = 12 x = 60. Its presence in the Peloponnese (Parnon, Taÿgetos, Menalon) and in the Pindhos mountains, Greece, was confirmed. Reports of plants with 2 n = 8 x = 40 from these stations seem to refer to the sterile hybrid V. reichenbachiana × sieheana which is locally abundant. V. caspia from Azerbaijan had 2 n = 8 x = 40 and had either whitish or blue flowers. In spite of sympatry and almost complete cross-compatibility, the two corolla colour morphs showed strong allozymic differentiation in four out of seven isozyme systems, suggesting reproductive isolation and incipient speciation. Within section Viola, V. caspia and V. sieheana seem no more closely related to each other than to either of the other investigated European species. The possibility that V. sieheana is an ancient allopolyploid involving the Greek narrow endemic V. dirphya (2 n = 40) is discussed. [ABSTRACT FROM AUTHOR]

The affinities of taxonomically problematic populations are typically analyzed using molecular markers. However these are less subject to selection than morphological characteristics. Consequently both approaches may be required to obtain a fuller picture of the identity and history of populations. Three putative hybrid populations within the Carex flava agg. are examined using such a dual approach with a view to elucidate their taxonomic affinities. Analysis of 11 morphometric characters using principal component analysis and examination of 17 isozyme loci revealed a more complicated history than that suggested by morphometric analysis alone. Results from this study confirm the status of an additional British population of C. flava s.str. and also strongly suggest that a population morphologically resembling Carex lepidocarpa has experienced the introgression of C. flava genes in the past. An Irish population resembling C. flava in appearance but lacking typical C. flava allozymes may be a result of local selection. [ABSTRACT FROM AUTHOR]

Many terrestrial orchids are relatively rare, and their populations are small and spatially isolated. Population genetics theory predicts that populations of such species, affected historically by random genetic drift, would maintain low levels of genetic diversity and exhibit a high degree of among-population divergence. To test this prediction, I used enzyme electrophoresis. Genetic diversity within populations of the four rare, terrestrial orchids Gymnadenia cucullata (four populations) and its congener G. camtschatica (four populations), Amitostigma gracile (four populations in one region and three in another region), and Pogonia minor (three populations each in two regions) was investigated in South Korea at the landscape level. As predicted, populations of the four species harbor low levels of genetic diversity within populations: the mean percentage of polymorphic loci, % P, the mean number of alleles per locus, A, and the average expected heterozygosity, He, were 12.5%, 1.13, and 0.036 for G. cucullata, respectively; 18.2%, 1.18, and 0.067 for G. camtschatica; 3.0%, 1.04, and 0.009 for A. gracile; and 2.7%, 1.06, and 0.014 for P. minor. Except for G. camtschatica ( FST = 0.000), a significantly high degree of genetic divergence between conspecific populations was detected in the other three species: FST = 0.081 for G. cucullata; 0.348 and 0.811 in two regions for A. gracile; and 0.469 and 0.758 in two regions for P. minor. In addition, individuals within populations are highly structured in the four species (overall FIS = 0.276 for G. cucullata; 0.308 for G. camtschatica; 0.758 for A. gracile; and 0.469 for P. minor), suggesting that selfing, biparental inbreeding, and/or consanguineous mating have occurred in populations of the four species. With the exception of G. camtschatica, an allele at a locus is fixed in a population, whereas alternative alleles with low or high frequencies are detected in another population across the landscape. My results suggest that evolutionary histories of G. cucullata, A. gracile, and P. minor are different from G. camtschatica. Historical genetic drift would be an important force shaping the genetic structure of the Korean populations of G. cucullata, A. gracile, and P. minor. For G. camtschatica on Ulleung Island, relatively higher levels of genetic variation within populations compared to its congener G. cucullata ( He = 0.067 vs. 0.036) and little evidence of population genetic structure among populations ( FST = 0.000) suggest that individuals were, presumably, once continuously distributed on Ulleung Island, and populations have recently been isolated by habitat fragmentation through natural succession (e.g,. probably the encroachment of woody vegetation on grasslands) or human-mediated disturbances (e.g., collections). Thus, conservation strategies for the four species should be differently developed in order to preserve genetic diversity in South Korea. [ABSTRACT FROM AUTHOR]

We combined reproductive and allozyme data to assess the levels and structuring of genetic variation and propose conservation guidelines in Limonium dendroides, a critically endangered Canarian endemic Plumbaginaceae featuring the floral and pollen pap/cob dimorphisms associated with the heteromorphic diallelic self-incompatibility system described for this family. Although seed germination has been reported in greenhouse conditions, the detection of individuals of only one morph in all wild subpopulations surveyed explains the extremely limited seed production and recruitment in nature. The geographical proximity and genetic closeness between some subpopulations, together with absence of inbreeding depression symptoms, and a higher allozyme variation in the cultured or reintroduced offspring than in their parental wild subpopulations indicate the viability of occasional compatible matings, thereby suggesting that even low levels of gene flow could mitigate the deleterious effects of fragmentation on subpopulation survival. However, our overall results indicate that L. dendroides is in a critical conservation situation where the utter scarcity of compatible mates within the subpopulations, radically low subpopulation sizes, poor inter-subpopulation gene flow, impoverished genetic variation, herbivore grazing, and the extreme habitat topography have overridden the reproductive capabilities of the species. According to our results, once morph types in all wild and cultured specimens can be determined, inducing fertile crosses through mixed reinforcements is advisable only in the most extremely isolated and small subpopulations (Argaga and Guarimiar) using individuals from the nearest ones (Azadoe and Palmarejo), whilst non-mixed reinforcements seem viable in the remaining subpopulations. Only when the subpopulations attain higher seed production and recruitment rates will it be adequate to collect seeds for their storage at a germplasm bank facility. [ABSTRACT FROM AUTHOR]

Since high levels of genetic diversity may ensure long-term survival of a plant species, it is essential to preserve the genetic diversity of the species. Tipularia japonica and Epipactis papillosa are rare terrestrial orchids in southern Korea with fewer than 50 mature individuals in a population and southern Japan and considered to be threatened (endangered or vulunerable). To obtain knowledge of how the genetic variation of these species is partitioned within and among populations in Korea, I used enzyme electrophoresis to examine the genetic diversity of each eight known populations of the two species from South Korea. Twenty-three ( E. papillosa) and 24 putative loci ( T. japonica) resolved from 15 enzyme systems revealed no variation either within or among populations of each species (0.0% of the percentage of polymorphic loci, %P). Previous studies, in contrast, showed that their more widely distributed disjunct congeners T. discolor and E. helleborine harbored high allozyme-based genetic diversity within populations in eastern United States ( %P = 75%) and in Denmark ( %P = 73.6%), respectively. In theory, small population size leads to allelic fixation at many loci over generations within a population, resulting in population genetic divergence or differentiation. In this regard, the complete lack of genetic differences between conspecific populations of T. japonica and E. papillosa cannot be explained by genetic drift. Instead, the present allozyme data suggest that recent origin from the same genetically depauperate ancestral or source population could result in this observation. The current status of T. japonica and E. papillosa (rarity and lack of genetic variation) significantly threatens the long-term survival of the species in Korea. [ABSTRACT FROM AUTHOR]

Espinhaço Range is a Brazilian chain of mountains, extremely rich in endemic species. Minasia has six species, all perennial herbs endemic to this range. Twenty-two populations were sampled from all Minasia species and assayed for allozyme variation. The species showed low genetic variation, compatible with the expectation for endemics. Genetic identities in Serra do Cipó and Diamantina were high, even between populations of different species. On the other hand M. cabralensis, from Serra do Cabral, was more differentiated from the other species. We also observed a marked genetic differentiation within M. cabralensis. Most strikingly, two close populations of this species showed very different allele frequencies. Our findings highlight the importance of local differentiation in campos rupestres. The observed genetic structure indicates that substantial portions of genetic diversity could be lost with the extinction of only one population, which is especially threatening considering the already low genetic diversity. [ABSTRACT FROM AUTHOR]

Pilosella alpicola subsp. ullepitschii (Asteraceae) is a strictly allogamous, diploid Carpathian endemic. Its distribution range comprises two areas separated by about 600 km. While in the Western Carpathians (Slovakia and Poland) the taxon occurs in numerous sites, only four localities of man-made origin are known from the Eastern and Southern Carpathians (Romania). We used allozyme markers to test two likely possible scenarios for the origin of this disjunction: long distance dispersal and vicariance. Our data indicate a significant loss of genetic diversity in the isolated Eastern and Southern Carpathian populations in following genetic parameters (averaged per region): percentage of polymorphic loci (38.9% found in the Eastern and Southern Carpathians versus 58.3% in the Western Carpathians), allelic richness (1.4 vs. 1.6), expected heterozygosity (0.134 vs. 0.235), mean number of distinguishable multilocus genotypes (4.3 vs. 10.6) and proportion of distinguishable multilocus genotypes (0.34 vs. 0.68). Higher proportion of homozygous loci found in the Eastern and Southern Carpathian populations might indicate a higher rate of inbreeding due to non-random mating. We assume that these genetically depauperate populations have experienced a very strong genetic bottleneck, probably due to a founder effect. Although our data suggest that the long-distance dispersal model is most likely, more discriminate genetic markers should be used to test this further. [ABSTRACT FROM AUTHOR]

Raddia brasiliensis forms a species complex with the recently segregated R. megaphylla, R. lancifolia, R. soderstromii and R. stolonifera, occurring in the Atlantic rainforest, Brazil. Allozymic markers were used in 272 individuals of 14 populations of this group to investigate its genetic variability, correlating this with morphological variability, and testing the proposed taxonomy based on multivariate morphometrics. Genetic variability was low in almost all populations ( P = 22.2–66.7, A = 1.3–2.0, H e=0.04–0.17). R. brasiliensis showed a very high endogamy ( F IS = 0.329). Values for genetic and morphological structuring were very high to high ( F ST = 0.43, A MRPP = 0.22; F ST = 0.19, A MRPP = 0.10 and F ST = 0.18, A MRPP = 0.39), respectively, for R. brasiliensis, R. soderstromii and R. megaphylla. The lowest genetic identity between populations was also found in R. brasiliensis, and the highest morphological differentiation was found between populations of R. megaphylla. Allozymic and morphological data were congruent and complementary, and confirm that we are dealing with five distinct species as previously circumscribed. [ABSTRACT FROM AUTHOR]

To date, empirical studies on levels of genetic diversity in highly isolated populations of lithophytic orchids are few. We investigated levels of allozyme diversity and spatial distribution of genotypes in small, isolated populations of the endangered, self-compatible lithophyte Amitostigma gracile from southern Korea. At the regional level, genetic diversity was extremely low within nine populations (mean expected heterozygosity, H e = 0.005); among 20 putative loci screened, only one locus ( Dia-1) was polymorphic. At this locus Dia-1 a was fixed in two populations, whereas Dia-1 b was in four populations, which as well as the scarcity of genetic variation might be indicative of random genetic drift. Similarly, at the landscape level, Dia-1 a was fixed in a population, whereas Dia-1 b with a high frequency (0.917) was detected in another population (two populations were separated by only 150 m). Analysis of fine-scale genetic structure within populations revealed significant declines in kinship with distance, suggesting that most seeds fall around maternal plants. Furthermore, a significantly high degree of population differentiation and a considerable deficit of heterozygosity were found among and within populations ( F ST = 0.857; F IS = 0.940). These results suggest that genetic drift as a consequence of a small effective population size (genetic bottleneck), coupled with a limited gene flow would be major factors in harboring extremely low levels of genetic variation and in the shaping of population genetic structure of A. gracile in South Korea. [ABSTRACT FROM AUTHOR]

Chamaecrista sect. Absus subsect. Baseophyllum (Leguminosae–Caesalpinioideae) includes eight species with geographic distribution concentrated in the Cadeia do Espinhaço mountain range of the States of Bahia and Minas Gerais, in eastern Brazil. During the taxonomic revision of this group, individuals were encountered with intermediate morphology between three sympatric species. Allozyme and multivariate morphometric analyses were carried out to investigate the occurrence of hybridization between these species in four populations and 14 suspected hybrid individuals between C. confertiformis and C. depauperata and between C. blanchetii and C. confertiformis. The results of both analyses support the occurrence of natural hybridization between them, and that all the individuals with intermediate morphology are probably F1 hybrids. The hybrids are formally described as C. × blanchetiformis and C. × patyensis. [ABSTRACT FROM AUTHOR]

We carried out genetic and morphometric analyses in 33 populations belonging to all nine described and one putative taxa of Chamaecrista subsect. Baseophyllum. Genetic variability was low in all taxa. Morphological and genetic data are consistent with the status of C. depauperata and C. coriacea. However, divergence between C. cytisoides var. cytisoides and all the other six conspecific varieties is higher than the divergence between it and the other two species. Our data support the recognition of eight species in the subsection Baseophyllum. Chamaecrista coriacea and C. depauperata are supported in their original circumscription. However, the varieties ascribed to C. cytisoides are best treated as six different species. We propose five new combinations in order to raise varieties of C. cytisoides to specific rank: C. blanchetii, C. brachystachya, C. confertiformis, C. decora, C. unijuga. We also propose synonimization of one variety, C. cytisoides var. micrantha, under C. brachystachya. [ABSTRACT FROM AUTHOR]

The Bulbophyllum exaltatum complex comprises 15 described taxa, and present a number of unresolved taxonomic questions, especially among populations found in the Brazilian campo rupestre vegetation. Allozymes were examined in 33 populations to determine the degree of genetic variability between them and their degree of differentiation to better define the taxa of this group. Additionally morphometric analyses were also performed on representatives of 24 populations. All of the populations examined demonstrated high levels of variability and none of the species formed distinct groups comprising all of the conspecific populations. However, the populations primarily grouped according to their regional occurrence, with a distinction between populations of the states of Minas Gerais and Bahia, which coincided with the geophysical disjunction of the mountain chains where they occur. It is probable that hybridization or incipient differentiation is contributing to the elevated genetic identity observed among the populations, generating a reticulated grouping pattern. [ABSTRACT FROM AUTHOR]

The Beaver Island Archipelago (BIA) provides a model system to address the impact of long-term isolation on genetic diversity and gene flow. Low lake levels are assumed to have caused the BIA to be attached to mainland Michigan for at least 4000 years (10000 yr B.P.- 6000 yr B.P.), eventually, rising lake levels would have kept the islands isolated since 6000 yr B.P. If the island populations of a plant species in the BIA were indeed once continuous with the mainland of Michigan, then we would expect similar levels of genetic diversity in populations of such a species on the islands vs. the mainland. We compared levels of allozyme genetic diversity of 20 plots of Pinus strobus in the BIA with two mainland populations in northern Michigan. In addition, if pollen is a primary agent of gene flow across islands, a low degree of allozyme differentiation among the island populations of P. strobus in the BIA would be evident. Furthermore, since seed dispersal is more limited than pollen dispersal in P. strobus, a more pronounced spatial genetic structure (SGS) is expected in allozymes than in cpDNA markers. To gain insights on the pattern of seed and pollen dispersal among the 20 plots, we further analyzed spatial autocorrelation using Moran's I-statistics for both data sets [biparentally inherited, allozymes and paternally inherited, cpDNA microsatellites (cpDNA SSR)]. We found a similar level of allozyme variability in both the BIA (mean H e = 0.080) and the two mainland populations (mean H e = 0.078). As predicted, we observed a low but significant degree of genetic divergence among populations for allozymes (mean F ST = 0.033 across 20 plots). Our allozyme-based SGS analysis revealed significant evidence of SGS (i.e. isolation-by-distance; slope β = −0.194 from regression analysis of observed averaged Moran's I values against the logarithm of the upper bound of six distance classes). In contrast, little evidence of SGS was found in cpDNA SSR data across the BIA ( β = 0.013). These results suggest that although gene flow via seed dispersal is somewhat limited, pollen flow has been sufficient to maintain genetic diversity and prevent differentiation across the island landscape over several thousand years of isolation. [ABSTRACT FROM AUTHOR]

Genetic variation in 13 populations of a Balkan endemic, Serbian spruce ( Picea omorika (Panč.) Purk.), was investigated using 16 isozyme loci. Serbian spruce is characterized by low levels of genetic variation (average proportion of polymorphic loci was 20.9% and average expected heterozygosity was 0.067). In most populations, a significant surplus of heterozygotes was observed, indicating a strong selection against inbreds. In the largest populations, fixation indices were positive, probably due to within-population differentiation and the associated Wahlund effect. Despite a strong overall differentiation ( F ST =0.261), no geographical trends in the genetic variation could be identified. Genetic drift caused by small effective population sizes and a strong fragmentation is the most plausible explanation for such variation patterns. A Bayesian analysis of population structure revealed the existence of two clusters, which are supposed to be possible remnants of ancient differentiation within a large range of the predecessor of Serbian spruce, Picea omoricoides Weber. Ex situ conservation measures, namely establishing seed orchards from trees of mixed origin, are proposed as a necessary complement to in situ protection of natural stands. [ABSTRACT FROM AUTHOR]

The first proven data on natural hybridization in the genus Hieracium s. str. are presented. Plants with intermediate morphological characters between the diploids H. alpinum and H. transsilvanicum were found in the Muntii Rodnei (Romanian Eastern Carpathians) in 2001 and in the Chornohora Mts (Ukrainian Eastern Carpathians) in 2003. While plants of intermediate morphology between usually so called basic species are usually tri- or tetraploid in Hieracium s. str., these plants were diploid (2n=18) like both parental species in this region. The Romanian plant did not produce fertile achenes in free pollination and in control backcrosses with H. transsilvanicum, two hybrids from Ukraine were completly seed sterile in free pollination and reciprocal crosses. Pollen stainability as an indirect measure of male fertility was quite high in the studied Ukrainian hybrid plants and similar to the parental taxa. Evidence from allozyme analysis also confirmed the hybrid origin of the studied plants. Sequencing and PCR-RFLP analyses of the trnT- trnL intergenic spacer revealed that all hybrid plants had the H. transsilvanicum chloroplast DNA haplotype. Maternal inheritance of chloroplast DNA in this particular cross was proved with artificial hybrids from reciprocal experimental crosses between H. alpinum and H. transsilvanicum. In both localities, the natural hybrid plants were found in disturbed habitats, exceptionally allowing contact of the otherwise ecologically vicariate parental species. Morphologically, the hybrid plants belong to H. × krasani Woł. [ABSTRACT FROM AUTHOR]

Orchid seeds are minute, dust-like, wind-borne and, thus, would seem to have the potential for long-distance dispersal. Based on this perception, one may predict near-random spatial genetic structure within orchid populations. In reality we do not know much about seed dispersal in orchids and the few empirical studies of fine-scale genetic structure have revealed significant genetic structure at short distances (< 5m), suggesting that most seeds of orchids fall close to the maternal plant. To obtain more empirical data on dispersal, Ripley’s L( d)-statistics, spatial autocorrelation analyses (coancestry, fij analyses) and Wright’s F statistics were used to examine the distribution of individuals and the genetic structure within two populations of the terrestrial orchid Orchis cyclochila in southern Korea. High levels of genetic diversity ( He = 0.210) and low between-population variation were found ( FST = 0.030). Ripley’s L( d)-statistics indicated significant aggregation of individuals, and patterns varied depending on populations. Spatial autocorrelation analysis revealed significant positive genetic correlations among individuals located <1 m, with mean fij values expected for half sibs. This genetic structure suggests that many seeds fall in the immediate vicinity of the maternal plant. The finding of significant fine-scale genetic structure, however, does not have to preclude the potential for the long distance dispersal of seeds. Both the existence of fine-scale genetic structure and low FST are consistent with a leptokurtic distribution of seed dispersal distances with a very flat tail. [ABSTRACT FROM AUTHOR]

We examined the genetic variation of 12 isozyme loci in 14 populations of Matthiola (Brassicaceae) representing the geographic distribution of the species M. incana, M. fruticulosa ssp. fruticulosa and M. tricuspidata in the Sicilian insular system and the adjacent mainland areas to estimate the levels and apportionment of genetic variation in the insular populations and to understand their population dynamics. The disparity in the distribution of polymorphism in populations of M. incana ssp. incana (low within populations but with high values of F ST and G ST) contrasts with the homogeneity in the inter-population distribution of the high genetic variation detected in M. tricuspidata and M. fruticulosa ssp. fruticulosa. While the low polymorphism found in M. incana ssp. incana is consistent with its origin through cultivation and the associated lack of gene flow, the Sicilian populations of the other two taxa probably derived from multiple founder events from nearby continental areas and, according to our estimates, have maintained high interpopulational gene flow. Unlike M. incana, the Sicilian populations of M. tricuspidata and M. fruticulosa ssp. fruticulosa could have survived the glaciations in refugia. This higher antiquity, together with the maintenance of abundant gene flow, largely explains their high values of genetic variation. In contrast, M. incana ssp. pulchella and M. incana ssp. rupestris have low indices of polymorphism and they are probably neo-endemics, as their distribution areas were severely affected by the Plio-Pleistocene glaciations. [ABSTRACT FROM AUTHOR]

Patterns of allozyme variation have been investigated in 101 clones representing most of the morphological variation (and taxa) found in the amphi-apomictic genusPilosellaHill. in the Nordic countries. Levels of variation were very high, both within narrowly defined taxa and within the whole data-set, but the correlation between a morphology-based taxonomy and patterns of allozyme variation was very weak. Almost all enzyme bands were found in more than one taxon and the differences between broadly defined species in terms of the frequency of bands were generally small. Cluster analyses did not perfectly recover any taxon but there were some tendencies for samples of some broadly defined taxa (e.g.P. officinarums. l., andP. cymosassp.cymosa) to cluster together. It is concluded that there is considerable gene-flow among virtually all Nordic morpho-types ofPilosellaand this is considered an argument for applying a very broad species concept in this genus. [ABSTRACT FROM AUTHOR]

Considerations of colonization history of an oak species across multiple populations would provide insight into whether different population histories generate near random or significant fine-scale spatial genetic structure. This study used multilocus allozyme genotypes mapped from three populations ofQuercus dentatain South Korea: one population, in Mt. Sobaek (SOB), is considered to be recently established from “off-site” seed sources; the second population, located in Dongraedo (DON), Jollanamdo Province may have been established from “on-site” old individuals; and the last population, in Haegumgang (HAE), Gyeongsangnamdo Province, is probably in an intermediate stage between SOB and DON. Coancestry measures (fij), Ripley’sL-statistics, and Wright’sFstatistics were calculated to examine the distribution of individuals and spatial genetic structure both within and between populations. Ripley’sL-statistics indicated significant aggregation of individuals, and patterns varied depending on populations. A significant positive fine-scale genetic structure at 10 m distance was detected in population DON, whereas SOB and HAE populations mostly showed very weak patterns and indeed genotypes were essentially randomly distributed. These results appear to be consistent with the proposed histories of population establishment. The levels of genetic diversity within populations ofQ. dentataexamined in this study (He=0.103) were lower than in most of the oaks, which may reflect rarity and discontinuity in the distribution ofQ. dentata. A small but significant deficit of heterozygosity was detected within populations (pooledFIS=0.040), which is also consistent with most of the examined oaks. Low but significant differentiation between the three populations ofQ. dentata(meanFST=0.030) agrees with that found for other oaks in South Korea, reflecting long-distance pollen movement by wind. [ABSTRACT FROM AUTHOR]

Enzyme electrophoreses were used to estimate genetic variation in five populations of Epipactis helleborine from two National Parks (Biebrza and Wigry) in northeast Poland. it has been proved that populations from these two regions differed in genetic structure, with the populations belonging to the Biebrza group having a higher level of genetic variation than those from Wigry. The number of polymorphic loci (P) ranged from 18.2% to 40.9% and the mean number of alleles per polymorphic locus (Ap) from 2.25 to 2.80. Although the observed heterozygosity (Ho) was lower than the expected one (He) in each population, the values of Ho and He were 2–3 times lower in the populations from Wigry than in those from Biebrza. Excluding the LUK population with the smallest genotypic diversity, the majority of 345 distinct multilocus genotypes occurred only once, sporadically 2–4 times in each population and their frequency ranged from 0.2% to 3.7%. Moreover, factors shaping genetic structure of E. helleborine and their intensity varied in the populations studied. Reproduction from seeds seems to influence greatly the genetic variation of the populations from the Biebrza National Park, while an assortative mating between related individuals or population size appears to be more important in the case of the populations from the Wigry National Park. [ABSTRACT FROM AUTHOR]

Allozyme variation in 83 European populations of the Melica ciliata/ transsilvanica species complex has been investigated. In spite of a diploid chromosome number, most loci were duplicated and patterns of within-population variation were not explainable unless apomixis or uncommon patterns of chromosomal segregation were assumed. Allelic richness and genetic diversity were very high but most of the variation (55–98%) was due to population differentiation. Geographic patterns were analysed both using phenetic, based on allele frequencies within populations, and cladistic, based on multi-locus genotypes, methods. Both methods congruently recognised three large groups of populations with discrete geographic distributions, in addition to a number of smaller groups. Of the three main groups, one was distributed in eastern and central Europe, one was restricted to western Europe north of the Alps and one was distributed in Iberia, Brittany and along the western shores of the Mediterranean. These groups are likely to have had separate histories but there appears to have been significant gene-flow among them. Among the less distinct groups, it was suggestive that some, e.g. the group containing all populations from the disjunct distribution in the Baltic basin, have been formed by introgression between the three major groups, whereas other deviating populations may represent additional distinct entities. [ABSTRACT FROM AUTHOR]

Corylus avellana L. (hazel, Betulaceae) is a long-lived, widespread shrub in Europe, having its northern range margin in Fennoscandia and a postglacial history involving range-expansion from refugial areas in southern Europe. In this study, we tested for a relationship between marginality and low within-population genetic diversity by assessing patterns of variation at 14 putatively neutral allozyme loci (comprising 43 putative alleles) within and between 40 natural populations of C. avellana along a north-south transect in Europe. Geographically marginal populations (central Sweden) showed lower levels of within-population diversity than populations in more central regions, as indicated by significant negative correlations between latitude and the percentage of polymorphic loci (rS=–0.47, P < 0.001), the average number of alleles per locus (rS=–0.65, P < 0.001), the expected heterozygosity (rS=–0.19, P < 0.05), and the proportion of distinguishable genotypes (rS=–0.56, P < 0.001). These patterns, combined with the unusually high between-population component of gene diversity (GST=19.7%) and allelic richness (AST=24%) in the marginal region, can be attributed to historical bottlenecks during the species’ postglacial range-expansion, but may also reflect a history of genetic drift in the small, isolated populations occupying the marginal region. Information on the spatial distribution of genotypes provide further support for a role of vegetative reproduction (layering) in the structuring of genetic variation within populations. [ABSTRACT FROM AUTHOR]

Nineteen from the ca. 30 Diplotaxis species including all known haploid chromosome numbers have been analysed for isoelectric focusing patterns of Rubisco, allozymes and RAPDs. D. erucoides (n=7) was clearly separated from all other species as were D. harra and D. crassifolia (n=13 each). Taxa with n=8 had different IEF patterns, but allozyme data grouped D. siettiana, D. ibicensis and D. brevisiliqua together. Species with n=9 were characterised by different IEF patterns, and their position was neither resolved in the allozyme nor in the RAPD tree. Only the D. catholica accessions were strongly clustered together. D. viminea and D. siifolia (both n=10) were kept separate, whereas the n=11 taxa D. tenuifolia, D. cretacea and D. simplex grouped together. Data confirm D. viminea as maternal parent of the allotetraploid D. muralis, and D. tenuifolia as the likely parent. [ABSTRACT FROM AUTHOR]

In Belgium, at the western border of its continental distribution range, the perennial herb S.nutans has evolved two parapatric ecotypes (calcicolous or silicicolous), which show contrasted allozyme, morphological and adaptive patterns, and isolating reproductive barriers. We examined allozyme variation in 21 populations close to Belgium (from France and Luxemburg) in relation to their peripheral or central geographical position, and investigated their genetic relationships with the Belgian ecotypes. Both peripheral and central populations showed high genetic variation. They were differentiated from each other, but not in relation to the substrate (calcareous or siliceous). The peripheral and central populations were related to the Belgian silicicolous and calcicolous ecotype, respectively. This suggests an ancient differentiation and different past histories for the Belgian ecotypes, and parapatric speciation processes. This study exemplifies the high evolutionary potential of populations at range peripheries and the need for considering them in conservation strategies. [ABSTRACT FROM AUTHOR]

A subset of populations of the European taxa of Carex sect. Digitatae, including Carex digitata, C. pallens, C. ornithopoda, C. pediformis ssp. rhizodes and C. humilis have been investigated for allozyme variation. The (presumably) distantly related C. pendula was used as a reference taxon. Carex digitata, C. pallens and C. ornithopoda on the one hand, and C. humilis and C. pediformis on the other, shared the majority of the alleles. Cluster analyses based on genetic distances grouped populations of C. digitata and C. ornithopoda in a mixed subcluster whereas all populations of C. pallens formed a subcluster distinct from the digitata/ornithopoda cluster. This in spite of the fact that C. ornithopoda is morphologically clearly distinct from C. digitata whereas C. pallens is barely distinguishable from the latter. Carex pediformis and C. humilis appeared not more genetically similar to C. digitata than to the reference taxon. It is concluded that 1) C. digitata, C. pallens and C. ornithopoda are closely related and most probably forms a monophyletic group, 2) C. pallens is a genetically distinct species, 3) C. pediformis and C. humilis are not closely related to the rest of C. sect. Digitatae, 4) C. pediformis and C. humilis are relatively closely related, 5) introgression do occur between the investigated species but not to such an extent that it can explain major geographic patterns of variation in C. digitata. [ABSTRACT FROM AUTHOR]

Taxa of the Viola alba complex were investigated using allozymes and morphometry. A taxonomic revision is presented. A wide delimitation of V. alba with only three morphological and geographical subspecies is suggested: (1) ssp. dehnhardtii distributed in the Mediterranean eastwards to Turkey; (2) ssp. alba flanking ssp. dehnhardtii in the north and east; and (3) ssp. cretica endemic to Crete. Ssp. cretica, up to now treated as a separate species, is particularly close to ssp. dehnhardtii. Viola cadevallii (NW Mediterranean) is included in the synonymy of ssp. dehnhardtii. Ssp. scotophylla (S Europe), ssp. thessala (Balkan), V. armena (Turkey), and V. besseri (Caucasus) are reduced to synonyms of V. alba ssp. alba. Viola pentelica (Greece) might represent transitional forms between ssp. alba and ssp. dehnhardtii. Glacial refugia for ssp. alba are suggested from the eastern Mediterranean via Turkey to the Caucasus, for ssp. dehnhardtii in the Mediterranean area in general, and for ssp. cretica in Crete. A key to the subspecies is provided. Taxonomic recombination: Viola alba Bess. ssp. cretica (Boiss. & Heldr.) Marcussen, comb. nov. [ABSTRACT FROM AUTHOR]

The geographic distribution of allozyme variation within the Eurasian boreo-nemoreal woodland grass Melica nutans L. has been investigated together with a minor subset of other Melica species. Twenty alleles were found at nine polymorphic loci in M. nutans. Allelic richness was highest in areas central in the species' European distribution, i.e. in southern Fennoscandia. High population densities, reducing the effects of genetic drift, as well as accumulation of variation through long-distance gene-flow from different marginal populations, is proposed to explain high allelic richness in this area. Several alleles showed geographic patterns in distribution and frequency variation. However, these patterns were not congruent, e.g. some alleles appear to have migrated to northern Europe from the south-west whereas others may have spread from the east. Genetic distances between geographic regions, each consisting of 2–6 populations, were generally low between all Fennoscandian, Russian and Siberian regions, but much higher between western and continental European regions. On the population level, cluster analysis grouped populations from Siberia, Russia, coastal and lowland areas in Fennoscandia and British Cumbria into one subcluster whereas other subclusters contained mainly south-west European populations or populations from almost throughout the distribution range. A scenario with several independent glacial refugia in central Europe, south-western Siberia and possibly western Norway, and subsequent colonisation of Fennoscandia mainly from the east, but with some long-distance gene-flow from central Europe, is proposed. [ABSTRACT FROM AUTHOR]

Material of Dactylorhiza were sampled from 49 localities in Turkey and investigated for allozyme variation at ten loci (nine enzyme systems). Among diploids, the Anatolian D. osmanica and D. umbrosa were allozymically variable, but not distinct from each other or from D. incarnata. Dactylorhiza saccifera contained the same alleles as the European D. fuchsii. Dactylorhiza iberica and D. euxina were distinct from each other and the other diploids. On basis of allozyme patterns three distinct allotetraploid genotypes were distinguished, and each of them could be treated as a separate species. Dactylorhiza nieschalkiorum is similar to European allotetraploids, and may have arisen from hybridization between D. incarnata s.l. and D. saccifera. Dactylorhiza urvilleana may have arisen from parents related to present-day D. saccifera and D. euxina, but it also contains additional alleles that have not been found in any of the diploids investigated. A third allotetraploid known from four populations in the Ardahan and Kars provinces of north-eastern Turkey combines the allozyme patterns found in material of D. incarnata s.l. from the same area with those from D. euxina. It is here described for the first time as D. armeniaca. [ABSTRACT FROM AUTHOR]

Lathyrus vernus (L.) Bernh. is a diploid, long-lived perennial and insect-pollinated herb with no special adaptation to long-distance dispersal. It occurs on neutral soil in deciduous forests throughout western Eurasia. Due to specific habitat preferences, L. vernus has a fragmented distribution with isolated populations. We investigated allozyme variation at eleven loci in 20 populations of L. vernus from one geographically central region (the Czech Republic and the Slovak Republic) and two geographically marginal regions (southern and central Sweden) in the species present-day distribution. There was a clear differentiation between the three regions and the genetic distance between the populations was highly correlated with geographic distance. The total genetic diversity (HT) was 0.354. The proportion of genetic diversity due to differentiation between regions, and to differentiation between populations within regions, accounted for 10% each. There was no difference in level of genetic diversity between the three regions. No significant difference in level of genetic diversity was found between small and large populations. The genetic diversity in L. vernus may either be a result of the long generation-time of the species or peculiarities in the post-glacial migration species, e.g. survival only in refugia far east of the sampled populations and/or migration as a continuous process not involving founder-events. [ABSTRACT FROM AUTHOR]

Allozyme markers from ten European taxa of Viola subsection Viola suggest that this group is allotetraploid, based on x = 5. All taxa had distinct multilocus phenotypes except V. alba subspp. alba and scotophylla, which were identical and different from subsp. dehnhardtii. Variation was consistently higher in Mediterranean populations than in North European ones. Hybridisation seems extensive but putative F1 hybrids were distinctly less fertile than the parental species. Nevertheless, increased fertility in later-generation hybrids and shared band patterns among taxa indicate an important role of hybridisation and introgression in past and present evolution within the subsection. The octoploid V. ambigua shows affinity to V. hirta (tetraploid). The octoploid V. suavis probably originated from V. pyrenaica and other unidentified tetraploids, and high variability suggests polytopy or even polyphyly. The stoloniferous condition (series Flagellatae) seems to be primitive in the subsection but the reduction of stolons (series Eflagellatae) may have originated multiple times. [ABSTRACT FROM AUTHOR]

In eight natural European populations of four closely related taxa of pines ( Pinus sylvestris, P. mugo, P. uncinata, and P. uliginosa) starch-gel electrophoreses revealed altogether 58 alleles at 15 loci from nine enzyme systems. With Nei's genetic distance (D) the largest mean genetic distance (D = 0.171) was found between P. sylvestris and P. mugo, a distance corresponding to that between other closely related pine species. Mean genetic distances between the other taxa were less than half that value and characteristic for subspecies or varieties rather than for species. On the basis of our results we suggest that both, P. uliginosa and P. uncinata, could be the result of the ancient hybridization between P. sylvestris and P. mugo. [ABSTRACT FROM AUTHOR]

RAPDs were employed as genetic markers to detect interspecific hybridization between the closely related oak species Quercus robur and Q. petraea. Fourteen primers were used in order to check the genetic status (“pure” or hybrid) of individuals classified morphologically. Among the 147 PCR fragments obtained 11 appear to be species-specific. In the phenotypically intermediate individuals different combinations of these species-specific bands were obtained. The patterns in these putative hybrids were not additive, which may be either the result of repeated backcrossing and introgression between the two species or of heterozygosity within the parental species. The results of the RAPD study are consistent with morphological analyses and allozyme data obtained for the Got-2 locus. Thus the RAPD markers used in this study may provide a powerful genetic tool for the identification of hybrids and the discrimination between the two “pure” species. [ABSTRACT FROM AUTHOR]

Genetic diversity in an insular endemic plant Aster asa-grayi was examined using enzyme electrophoresis. Distribution of A. asa-grayi is restricted to only four subtropical islands of Japan, and this species is listed as ‘vulnerable to extinction’ in the Red Data Book of Japanese wild plants. A total of 161 individuals were sampled from five populations on four islands. Genetic diversity values at the population level were very low, compared to other plant species with a similar life history. Genetic variability at the species level is comparable to the mean value of endemic species. Genetic differentiation among populations is extremely high (GST= 0.71), indicating that the gene flow among populations is highly impeded, and pollen and seed dispersal is limited due to the pollinators and the seed morphology. This is because the four islands are geographically isolated. Fixation indices suggested that most populations do not randomly cross. To conserve the genetic diversity of the species, artificial crossings among different island populations are necessary. [ABSTRACT FROM AUTHOR]

Genetic variability was estimated by enzyme electrophoresis in 239 Belgian clones from the Salix alba-S. fragilis complex. This morphological complex suggested a high frequency of hybrids. To test this hypothesis, the clones were pooled as a single co-adapted species complex and secondly as belonging to either species, i.e. being S. alba-like or S. fragilis-like. The standard genetic variability measures showed higher values for the complex than for the separate species. However, the observed mean heterozygosity was lower in the putative hybrid complex than for each of the species separately. The fixation indices were more variable at the species level and indicated that most S. fragilis locations appeared fixed for lap-1, whereas no fixation occured in S. alba locations. Averaged at the regional (i.e. catchment) level, this difference between the two species remained and values ranged from 0.457 to 0.617 in S. alba and were much higher, fixed homozygous or monomorph in S. fragilis. Hierarchical F-statistics revealed that most of the differentiation occured at the lower levels of localities and tributaries and that there was no further differentiation between catchments. Tributaries which are 10–25km in length were proposed as the most likely entities for further examination of putative hybridization and events of allelic fixations. By considering the two abovementioned approaches of data input, it could be suggested that most of the allozyme differentiation was between the species and less between the regions. [ABSTRACT FROM AUTHOR]

Medicago intertexta and M. ciliaris have been controversially recognized as separate species. The only reliable diagnostic character, gland-tipped trichomes on the fruits in M. ciliaris, is controlled by presence of a single dominant allele, and such one-character taxonomies are debatable. Contributing to the difficulty, M. muricoleptis and M. granadensis, the other two species of Medicago section Spirocarpos subsection Intertextae, are sometimes confusingly similar to M. intertexta or to each other. Allozyme differences provided 95% verification of the suitability of the gland-tipped trichome character for separating M. intertexta and M. ciliaris, thus corroborating their recognition as separate taxa. Several measures of allozyme variation indicated that M. intertexta is more polymorphic than its sister species. Heterozygosity was also highest in M. intertexta, suggestive of a higher outcrossing rate, which is also consistent with larger floral size. Heterozygosity of M. intertexta was concentrated in Sicily and nearby countries. Taxonomic difficulties in identifying Sicilian M. intertexta are well known, and may be the result of interspecific hybridization and introgression. Medicago muricoleptis differed from the above two species in the frequency of several alleles, while M. granadensis possessed numerous unique alleles consistent with its complete absence of genetic exchange with the other three substantially interfertile species. [ABSTRACT FROM AUTHOR]

Electrophoretic analysis of five enzyme systems, LAP, PGI, SKDH, SOD and 6-PGDH, among 102 Vicia accessions representing V. bithynica and seven species of the V. narbonensis complex, namely V. eristalioides, V. kalakhensis, V. johannis, V. galilaea, V. serratifolia, V. narbonensis and V. hyaeniscyamus, has been performed. The recorded variation was tentatively assigned to 41 allelic genes at eight loci; intraspecific variation was observed in all species except for V. eristalioides. The results obtained were compared with the corresponding data reported earlier for V. faba. Hierarchical grouping of the investigated taxa, including V. faba, was based on Nei's genetic identities calculated from the allozyme frequency data. Vicia faba and V. bithynica were shown to be most distantly related to one another and to the remaining species investigated. Vicia serratifolia appeared to be a peripheral member of the V. narbonensis complex. The results are discussed with reference to genetic diversity and taxonomic relationships of the species under study. [ABSTRACT FROM AUTHOR]

The genetic relationships of Aechmea mexicana, A. lueddemanniana, A. macvaughii and A. tuitensis were investigated using starch gel electrophoresis. Eight enzyme systems encoded by ten putative gene loci were resolved in seventeen populations. Nei's (1978) genetic distances were obtained from allelic frequencies and used with UPGMA algorithm. Results indicate that some populations belonging to different species display genetic similarities closer to each other than to some conspecific populations. Our results do not support the proposed genus Ursulaea ( Read & Baensch 1994), since A. tuitensis was closer to A. lueddemanniana and A. mexicana than to A. macvaughii. [ABSTRACT FROM AUTHOR]

The genetic population structure in Bdallophyton bambusarum, an endoparasite, was studied in ten subpopulations from a subdeciduous tropical forest in Veracruz Mexico. The sample was analyzed using seven polymorphic loci in cellulose acetate electrophoresis. Isozyme data indicated that the subpopulations of B. bambusarum contained high genetic variability (Hep = 0.452 ± 0.045, S.E.). Our analysis suggests that almost each inflorescence of B. bambusarum is an individual. The subpopulations studied were genetically similar (average Nei's genetic identity 0.941 ± 0.051 and F st values 0.097 ± 0.026), suggesting that genetic differentiation among subpopulations was small. Direct estimates of effective population size was derived from observations of three fluorescent dyes, and from the genetic neighborhood area derived from these data. The neighborhood area, multiplied by the total density of individuals, gave an Ne = 124.84 plants, and when corrected to consider the proportion of males and females gave an Ne = 118.59 individuals. An indirect estimate of Nm was obtained from the F st values (mean Nm=2.037), giving an indirect estimate of the effective population size Nb = 12.8 individuals. Both values are relatively high when compared to other plant studies. The gene flow and/or effective populations size of the studied subpopulations of B. bambusarum are believed to be large enough to prevent differentiation among subpopulations due to genetic drift. [ABSTRACT FROM AUTHOR]

Isozyme electrophoresis was used to study the morphologically similar sister species Sphagnum rubellum and S. capillifolium from a sample of 1313 plants representing 37 populations from Scandinavia, Great Britain and S Germany. The mean pairwise genetic identities (I) among conspecific populations were 0.976 for S. rubellum and 0.969 for S. capillifolium, versus 0.627 between populations of the two species. Interspecific gene flow was indicated by the observation of occasional plants in sympatric populations with alleles otherwise unique to the other species. Populations of bisexual S. capillifolium were significantly more variable than populations of unisexual S. rubellum. Alpine populations of S. rubellum and S. capillifolium were dominated by few genotypes, and differentiation among populations was pronounced, indicating a low level of sexual recombination. In S. rubellum, maximum variability was found in western areas with high annual precipitation. Distribution of alleles in S. rubellum indicated restricted gene flow between Great Britain and Scandinavia. Postglacial migration from separate refugia may explain large-scale variation in S. rubellum. [ABSTRACT FROM AUTHOR]