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Spider dragline fibers exhibit incredible mechanical properties, outperforming many synthetic polymers in toughness assays, and possess desirable properties for medical and other human applications. These qualities make dragline fibers popular subjects for biomimetics research. The enormous diversity of spiders presents both an opportunity for the development of new bioinspired materials and a challenge for the identification of fundamental design principles, as the mechanical properties of dragline fibers show both intraspecific and interspecific variations. In this regard, the stress–strain curves of draglines from different species have been shown to be effectively compared by the α* parameter, a value derived from maximum-supercontracted silk fibers. To identify potential molecular mechanisms impacting α* values, here we analyze spider fibroin (spidroin) sequences of the Western black widow (Latrodectus hesperus) and the black and yellow garden spider (Argiope aurantia). This study serves as a primer for investigating the molecular properties of spidroins that underlie species-specific α* values. Initial findings are that while overall motif composition was similar between species, certain motifs and higher level periodicities of glycine-rich region lengths showed variation, notably greater distances between poly-A motifs in A. aurantia sequences. In addition to increased period lengths, A. aurantia spidroins tended to have an increased prevalence of charged and hydrophobic residues. These increases may impact the number and strength of hydrogen bond networks within fibers, which have been implicated in conformational changes and formation of nanocrystals, contributing to the greater extensibility of A. aurantia draglines compared to those of L. hesperus.

Arthropod silk is vital to the evolutionary success of hundreds of thousands of species. The primary proteins in silks are often encoded by long, repetitive gene sequences. Until recently, sequencing and assembling these complex gene sequences has proven intractable given their repetitive structure. Here, using high-quality long-read sequencing, we show that there is extensive variation—both in terms of length and repeat motif order—between alleles of silk genes within individual arthropods. Further, this variation exists across two deep, independent origins of silk which diverged more than 500 Mya: the insect clade containing caddisflies and butterflies and spiders. This remarkable convergence in previously overlooked patterns of allelic variation across multiple origins of silk suggests common mechanisms for the generation and maintenance of structural protein-coding genes. Future genomic efforts to connect genotypes to phenotypes should account for such allelic variation.

Arthropod silk is vital to the evolutionary success of hundreds of thousands of species. The primary proteins in silks are often encoded by long, repetitive gene sequences. Until recently, sequencing and assembling these complex gene sequences has proven intractable given their repetitive structure. Here, using high-quality long-read sequencing, we show that there is extensive variation—both in terms of length and repeat motif order—between alleles of silk genes within individual arthropods. Further, this variation exists across two deep, independent origins of silk which diverged more than 500 million years ago—(1) the insect clade containing caddisflies and butterflies and (2) spiders. This remarkable convergence in previously overlooked patterns of allelic variation across multiple origins of silk suggests mechanisms for the generation and maintenance of structural protein-coding genes. Future genomic efforts to connect genotypes to phenotypes should account for such allelic variation.

Morphological structures and extended phenotypes are made possible by materials that are encoded by the genome. Nearly all biomaterials are viscoelastic, which means that to understand performance, one must understand the strain rate-dependent properties of these materials in relevant ecological interactions, as the behavior of a material can vary dramatically and rapidly. Spider silks are an example of materials whose properties vary substantially intra- and inter-specifically. Here, we focus on aggregate silk, which functions as a biological adhesive. As a case study to understand how a material manifests from genome through organism to ecology, we highlight moth-specialist spiders, the Cyrtarachninae, and their glues as an ideal experimental system to investigate the relationship between genomics and ecologically variable performance of a biological material. There is a clear eco-evolutionary innovation that Cyrtarachne akirai and related species have evolved, a unique trait not found in other spiders, a glue which overcomes the scales of moths. By examining traditional orb-weavers, C. akirai and other subfamily members using biomechanical testing and genomic analysis, we argue that we can track the evolution of this novel bioadhesive and comment on the selection pressures influencing prey specialization. The importance of the ecological context of materials testing is exemplified by the poor performance of C. akirai glue on glass and the exceptional spreading ability and adhesive strength on moths. The genetic basis for these performance properties is experimentally tractable because spider silk genes are minimally pleiotropic and advances in genomic technologies now make possible the discovery of complete silk gene sequences.

In the taxonomic congruence approach to systematics, data sets are analyzed separately, and corroboration among data sets is indicated by replicated components in topologies derived from the separate analyses. By contrast, in the total evidence and conditional combination approaches, characters from different data sets are mixed in combined phylogenetic analyses. In optimal topologies derived from such simultaneous analyses, support for a particular node may be attributed to one, some, or all of the individual data sets. Partitioned branch support (PBS) is one technique for describing the distribution of character support and conflict among data sets in simultaneous analysis. PBS is analogous to branch support (BS), but recognizes hidden support and conflicts that emerge with the combination of characters from different data sets. For both BS and PBS, support for a particular node is interpreted as the difference in cost between optimal and suboptimal topologies. A different measure, the clade stability index (CSI), assesses the robustness of a particular node through the successive removal of characters. Here, we introduce variations of the CSI, the data set removal index (DRI) and nodal data set influence (NDI), that indicate the stability of a particular node to the removal of entire data sets. Like PBS, the DRI and NDI summarize the influence of different data sets in simultaneous analysis. However, because these new methods and PBS use different perturbations to assess stability, DRI and NDI scores do not always predict PBS scores and vice versa. In this report, the DRI and NDI are compared to PBS and taxonomic congruence in a cladistic analysis of 17 data sets for Artiodactyla (Mammalia). Five indices of hidden support and conflict are defined and applied to the combined artiodactyl character set. These measures identify substantial hidden support for controversial relationships within Artiodactyla. Hidden character support is ignored in the taxonomic congruence approach to systematics, but the DRI, NDI, and PBS utilize this cryptic information in estimates of support among data sets for a given node.

The evolutionary diversification of orb-web weaving spiders is closely tied to the mechanical performance of dragline silk. This proteinaceous fiber provides the primary structural framework of orb web architecture, and its extraordinary toughness allows these structures to absorb the high energy of aerial prey impact. The dominant model of dragline silk molecular structure involves the combined function of two highly repetitive, spider-specific, silk genes (spidroins)—MaSp1 and MaSp2. Recent genomic studies, however, have suggested this framework is overly simplistic, and our understanding of how MaSp genes evolve is limited. Here we present a comprehensive analysis of MaSp structural and evolutionary diversity across species of Argiope (garden spiders). This genomic analysis reveals the largest catalog of MaSp genes found in any spider, driven largely by an expansion of MaSp2 genes. The rapid diversification of Argiope MaSp genes, located primarily in a single genomic cluster, is associated with profound changes in silk gene structure. MaSp2 genes, in particular, have evolved complex hierarchically organized repeat units (ensemble repeats) delineated by novel introns that exhibit remarkable evolutionary dynamics. These repetitive introns have arisen independently within the genus, are highly homogenized within a gene, but diverge rapidly between genes. In some cases, these iterated introns are organized in an alternating structure in which every other intron is nearly identical in sequence. We hypothesize that this intron structure has evolved to facilitate homogenization of the coding sequence. We also find evidence of intergenic gene conversion and identify a more diverse array of stereotypical amino acid repeats than previously recognized. Overall, the extreme diversification found among MaSp genes requires changes in the structure-function model of dragline silk performance that focuses on the differential use and interaction among various MaSp paralogs as well as the impact of ensemble repeat structure and different amino acid motifs on mechanical behavior.

Background Spiders have evolved two types of sticky capture threads: one with wet adhesive spun by ecribellate orb-weavers and another with dry adhesive spun by cribellate spiders. The evolutionary history of cribellate capture threads is especially poorly understood. Here, we use genomic approaches to catalog the spider-specific silk gene family (spidroins) for the cribellate orb-weaver Uloborus diversus. Results We show that the cribellar spidroin, which forms the puffy fibrils of cribellate threads, has three distinct repeat units, one of which is conserved across cribellate taxa separated by ~ 250 Mya. We also propose candidates for a new silk type, paracribellar spidroins, which connect the puffy fibrils to pseudoflagelliform support lines. Moreover, we describe the complete repeat architecture for the pseudoflagelliform spidroin (Pflag), which contributes to extensibility of pseudoflagelliform axial fibers. Conclusions Our finding that Pflag is closely related to Flag, supports homology of the support lines of cribellate and ecribellate capture threads. It further suggests an evolutionary phase following gene duplication, in which both Flag and Pflag were incorporated into the axial lines, with subsequent loss of Flag in uloborids, and increase in expression of Flag in ecribellate orb-weavers, explaining the distinct mechanical properties of the axial lines of these two groups.

Some stalk-eyed flies in the genus Teleopsis carry selfish genetic elements that induce sex ratio meiotic drive (SR) and impact the fitness of male and female carriers. Here, we produced a chromosome-level genome assembly of the stalk-eyed fly, T. dalmanni, to elucidate patterns of genomic divergence associated with the presence of drive elements. We find evidence for multiple nested inversions along the sex ratio haplotype and widespread differentiation and divergence between XSR and XSR along the entire chromosome. These include a striking XSR-specific expansion of an array of partial copies of JASPer, a gene necessary for maintenance of euchromatin and regulation of transposable element expression (TEs). In addition, the genome contains tens of thousands of TE insertions and hundreds of transcriptionally and insertionally active TE families. Moreover, we find that several TE families are differentially expressed and/or present at a different copy number in SR male testes, suggesting an association between these two categories of selfish genetic elements in this species. We identify T. dalmanni orthologs of genes involved in genome defense via the piRNA pathway, including core members maelstrom, piwi and Argonaute3, that have diverged in sequence, expression or copy number between the SR and standard (ST) X chromosomes, consistent with altered TE regulation in flies carrying a sex ratio X chromosome. Overall, the evidence suggests that this ancient XSR polymorphism has had a variety of impacts on repetitive DNA and its regulation in this species.

Predictions of optimal foraging theory were tested for Peromyscus polionotus in the laboratory and in two field experiments in which seed item-size was manipulated. In the laboratory, handling times for millet, sunflower seeds, and peanuts were determined. Additionally, energy/handling (E/h) time values were calculated and seed preference experiments were conducted. Mice showed a clear preference for the seeds more profitable in terms of E/h. Seed preference experiments were also conducted in the field to determine the relative influence of optimal foraging and predation risk in diet choice. In the first of the two field experiments, behavioral strategies to reduce predation vulnerability could not influence differential seed selection. As predicted, the mice again showed a preference for the more profitable seed type. In the second experiment, animals were presented with conflicting demands because foraging on a more abundant, but less preferred, seed type afforded the animal an increased ability to avoid predators. Presented with this opportunity to reduce the risk of predation, the animals shifted their preference to the safer, but less profitable food. This shift in seed preference was accompanied by predation-risk-reducing changes in spatial foraging patterns.

Familial polyposis coli (FPC) is hereditary condition that conveys a virtual 100% risk for the development of colon cancer in the untreated patient. A total of 56 patients with FPC underwent complete ophthalmic examination. Highly pleomorphic pigmented retinal lesions were identified bilaterally in 52% (n = 29) and unilaterally in 14% (n = 8) of our subjects. In all, 33 patients had one or more extracolonic expressions associated with FPC, including desmoids, osteomas, epidermoid cysts, lipomas, fibromas, and upper gastrointestinal tract polyps. In 15 patients, pigmented fundus lesions were the only extracolonic manifestations. No significant association between eye findings and other extracolonic manifestations could be established. The presence or absence of pigmented fundus lesions was found to cluster within families. Pigmented fundus lesions are probably a variably penetrant expression of the polyposis gene and do not appear to be specifically associated with subgroups of inherited polyposis syndromes such as Gardner's syndrome.

Project Final Report for "100kW Energy Transfer Multiplexer Power Converter Prototype Development Project" prepared under DOE grant number DE-FG36-03GO13138. This project relates to the further development and prototype construction/evaluation for the Energy Transfer Multiplexer (ETM) power converter topology concept. The ETM uses a series resonant link to transfer energy from any phase of a multiphase input to any phase of a multiphase output, converting any input voltage and frequency to any output voltage and frequency. The basic form of the ETM converter consists of an eight (8)-switch matrix (six phase power switches and two ground power switches) and a series L-C resonant circuit. Electronic control of the switches allows energy to be transferred in the proper amount from any phase to any other phase. Depending upon the final circuit application, the switches may be either SCRs or IGBTs. The inherent characteristics of the ETM converter include the following: Power processing in either direction (bidirectional); Large voltage gain without the need of low frequency magnetics; High efficiency independent of output load and frequency; Wide bandwidth with fast transient response and; Operation as a current source. The ETM is able to synthesize true sinusoidal waveforms with low harmonic distortions. For a low power PM wind generation system, the ETM has the following characteristics and advantages: It provides voltage gain without the need of low frequency magnetics (DC inductors) and; It has constant high efficiency independent of the load. The ETM converter can be implemented into a PM wind power system with smaller size, reduced weight and lower cost. As a result of our analyses, the ETM offers wind power generation technology for the reduction of the cost and size as well as the increase in performance of low power, low wind speed power generation. This project is the further theoretical/analytical exploration of the ETM converter concept in relationship to PM wind power generator applications in the 100kW and under power range. The theoretical/analytical and bench scale work focuses on simplifying the basic ETM converter topology (in terms of parts count and complexity) for the specific application of the low power PM system. The project goals and objectives were for Spellman HV will develop a 100kW prototype ETM power converter based on paralleled lower ratings converters. The proposed configuration of this prototype is a 100kW rated converter comprised of four (4) 34kW rated modules connected in parallel (the fourth converter is included to demonstrate N+1 fault tolerance). This approach is more viable as there is lower technological risk involved in developing a 34kW-rated converter than a single 100kW unit. The modular system approach should have a lower deployment and service cost over a single unit system, because of the economics of scale (smaller units at a higher volume means lower manufacturing cost) and because of improved serviceability (a non-redundant power system with one failed module will still operate at a lower power level). There is also the added benefit that greater commercial application and acceptance should be achieved by having a modular system available in which fault tolerance (N+1 or 2N) is a feature. This modular approach would allow the output power to be increased by adding more paralleled converters. Thus, the maximum output power of the overall power system is a function of the interconnection medium (the hot swap connection subsystem), rather than the ratings of a single module. The project was implemented with Spellman HV acting as the program management and production assembly and test facility; The Baker Company acting as a technical consultant and resource when required; and dtm Associates acting as the design/development resource for the hardware development of the 100kW ETM converter prototype.

The utility of morphological data in modern systematics has recently been challenged because strong selection pressures are thought to create widespread patterns of convergent evolution at this level. This concern has led to suggestions that morphological data should be excluded either from all analyses or at least from analyses where there is conflict with molecular data. These concerns, however, are generally unwarranted and excluding data is not a defensible strategy for dealing with problems that do exist. We emphasize the importance of empirical responses, such as collecting additional and diverse data and exploring taxa and data set interactions, rather than the implementation of a priori assumptions, to overcoming many of the concerns associated with combining morphological and molecular data. Numerous factors may create biases in both molecules and morphology. While these biases are prevalent enough to cause widespread incongruence, they highlight the importance of combining, rather than separating, data. Morphological data also offer distinct advantages over molecular data, such as the inclusion of fossil taxa, cost-effectiveness and presence of biases different from those in molecular data.

The appropriate use of any test requires the clinician to appreciate that test's limitations. By recognizing the potential confounders of the auscultatory assessment of blood pressure, the clinician minimizes the likelihood of enacting therapeutic decisions based on inaccurate data. When approaching the treatment of a hypertensive patient, several points should be kept in mind. First, the measurement of persistent and severe hypertension in a patient receiving treatment who describes symptoms of orthostatic hypotension with apparently adequate standing blood pressure or who lacks corroborating retinal, echocardiographic, or electrocardiographic signs of hypertension should raise the concern of pseudohypertension or a white-coat response. Similarly, when one finds a normal or near-normal systolic blood pressure in a patient with a clinical picture consistent with severe hypertension, one should make a directed effort to look for an unrecognized auscultatory gap. Second, marked discrepancies in measurements as obtained by different operators or in different settings should raise concern of the white-coat response or methodologic errors by one operator, such as undercuffing, excessive pressure on the head of the stethoscope, rapid deflation of the cuff, or use of different arms. In treating hypertension in even the minimally obese patient, a special point must be made that an adequate size cuff be used for all blood pressure determinations. Third, when blood pressure is determined with the patient in any but the satndardized back-and-arm-supported seated position described above, the clinician should acknowledge the possibility that the position may alter the patient's classification. Fourth, the diagnosis and management of hypertension requires multiple measurements of blood pressure.(ABSTRACT TRUNCATED AT 250 WORDS)

A nonimmune American acquired an infection of Plasmodium vivax Type 1 malaria in Brazil in 1994. After returning to the U.S.A., he had a primary attack followed by 3 relapses. The primary attack and first 2 relapses were treated with a standard regimen of chloroquine, followed by 14 days of primaquine (15 mg/day). Following the third relapse, the primaquine treatment was extended to 28 days. No further relapses occurred. The lack of response to primaquine by this strain may recommend it as a suitable candidate for chemotherapeutic study if it can be adapted to an animal model. Anopheles quadrimaculatus mosquitoes infected by feeding on the patient during the first relapse were used to establish the strain in Aotus and Saimiri monkeys. Monkeys supported well the development of long-lasting parasitemia. Anopheles freeborni, Anopheles stephensi, and Anopheles gambiae mosquitoes were readily infected by feeding on the monkeys and by membrane feeding on diluted blood. Monkey-to-monkey transmission was obtained via the bites of infected mosquitoes and the intravenous injection of sporozoites dissected from salivary glands. This parasite is designated as the Brazil I/CDC strain of P. vivax.

The genetic and linkage analyses of an alpha and beta esterase polymorphism in Anopheles culicifacies are presented. A survey of laboratory strains uncovered four electrophoretic variants for the alpha esterase and two for the beta esterase. Genetic analyses indicated that the variants of the alpha esterase are under the control of codominant alleles of a single locus and that this locus is linked to the locus controlling the expression of the codominant alleles of the beta esterases. The esterases are not linked either to sex (chromosome 1) or to maroon eye (chromosome 2) but to the chromosome 3 markers, dieldrin resistance and phosphoglucomutase. The gene sequence is Est-alpha--Dl--Pgm--Est-beta dnd the recombination frequencies are as follows: Est-alpha--Dl = 2.9 percent; Dl--Pgm = 5.8 percent; Pgm--Est-beta = 6.4 percent; Est-alpha--Est-beta = 15.1 percent, Est-alpha--Pgm = 8.7 percent and Dl--Est-beta = 12.2 percent.

Four wild type laboratory strains from Japan appear to have the sex allele M on the third chromosome while all but 1 strain from Pakistan, Bangladesh, and Taiwan have the sex allele on chromosome 1. The one exceptional Pakistan strain with sex on chromosome 3 may be the result of an earlier laboratory contamination from Japanese strains.

A total of 167,291 Culex tritaeniorhynchus Giles males heterozygous for a M 3 (male) linked complex aberration with 80–90% sterility was released daily over a 2-wk period to ascertain their mating competitiveness in nature. A dominant temperature sensitive lethal was employed as the primary sexing method for the release males. Competitiveness was determined by releasing both fluorescent dye dusted laboratory colonized virgin females and virgin female F1 progeny of wild caught females as well as by sampling endemic females in the study area. Matings by released males were confirmed by egg sterility and genetically by a recessive marker closely linked to the M 3 allele. Released males were highly competitive with released laboratory colonized females but were uncompetitive with the wild females, which suggested that colonization and/or prolonged laboratory maintenance had selected an assortive mating behavior. These results underscore the importance of using wild females to evaluate the competitiveness of altered genotypes and of incorporating as much endemic genetic material as possible into the release genome.

Genetic analysis indicates that dieldrin resistance in laboratory colonies of Anopheles culicifacies is under the control of codominant alleles of a locus in linkage group 3 (chromosome 3), approximately 31 map units from Acph (acid phosphatase).

During late autumn 1978, male Culex tritaeniorhynchus carrying a complex chromosomal re-arrangement (In(3)T(2,3)l) were outcrossed to a newly established hybrid stock and released at the village of Shah-di-Khoi near Lahore. Mating competitiveness in nature was assessed using marked virgin sibling females, the marked virgin female progeny of wild-caught females and unmarked females collected biting buffaloes at Shah-di-Khoi. The released males were competitive for their sibling females, but were uncompetitive for the progeny of wild-caught females as well as the unmarked females, even when the sample size was adjusted for emergence and parity. These results suggest that the genome enabling mating under insectary conditions was rapidly selected and fixed, leading to the observed assortative mating.

Fifty-eight translocations were produced and studied using improved genetic and cytogenetic techniques now available for Culex tritaeniorhynchus. Data confirm previous chromosome-linkage correlation studies and indicated that the e locus is on the long arm (2R) of chromosome 2.

Males of Anopheles culicifacies Giles carrying a complex chromosomal rearrangement in a laboratory adapted genetic background ( In-l/T-1 ) were released at a cattle compound in rural Punjab Province, Pakistan, to test their mating competitiveness (e) against both the released virgin male progeny of wild caught females (WC) and endemic (UM) males for released laboratory-adapted (KB) and WC females. When In-l/T-1 ♂ ♂, WC ♀ ♀ and KB ♀ â♀ were entrained on an aberrant insectary photoperiod, the In-l/T-1 ♂ ♂ were supercompetitive (e>l); however, when reared under a natural photoperiod, In-l/T-1 ♂ ♂ were equally competitive (e = 1). Throughout there was no significant difference in e estimated by either WC or KB females, indicating that an aberrant mating behavior had not been selected during colonization and insectary maintenance. Most released females mated in the immediate vicinity of the diurnal resting site during or just after the crepuscular egress. Few UM ♀ ♀, or WC ♀ ♀ released as pupae at a breeding site, were inseminated by In-l/T-1 ♂ ♂ indicating that some mating must occur elsewhere or at different times of the night.

Genetic and cytogenetic investigations of two unstable Y-linked translocations in Anopheles culicifacies indicate that crossing over can occur between the X and Y chromosomes in this species. Moreover, these observations suggest that the long arms of the X and Y chromosomes are homologous and that the sex determining mechanism(s) is located in the short arms.

The genetic analysis of two new mutants, brown and abnormal eye, is presented. The data indicate that both mutants are recessive and under the control of loci in linkage group III. The gene sequence for linkage group III is cl-Adh-s-bw-ae. The total length of linkage group III is now approximately 48 map units. Mosquitoes homozygous for both brown and rose, another eye-color mutant in linkage group I, exhibit a third new phenotype, yellow-orange eye.

The genetic analysis of an EMS-induced, recessive, sex-linked eye mutant, rose eye (re), is presented. This locus is closely linked to maroon eye (approximately four map units apart). Individuals homozygous for both rose- and maroon-eye exhibit a third phenotype, white to pale pink eyes.

Chemosterilized Anopheles culicifacies Giles males carrying a Y-linked, dieldrin genetic sexing device (D-13) were released concomitantly with a laboratory-adapted strain (SAT) and the progeny of wild-caught females (KB) as pupae through a self-dusting device positioned at a breeding site near Kot Baghicha Singh Walla, Pakistan during April 1980. Some dusted SAT and KB ♀ ♀ were also released as virgin adults inside diurnal cattle shed resting sites. Emerging D-13 ♂ ♂ behaved similarly to endemic unmarked males (UM); i.e., they rested outdoors until sexually mature, immigrated into a cattle-shed compound where they swarmed with UM ♂ ♂ and rested indoors on the following day in equal proportions to swarm composition. In addition, equal proportions of D-13 and UM ♂ ♂ mated at each collection site. However, estimates of mating competitiveness based on the fertility of egg batches from individual SAT, KB and UM ♀ ♀ were statistically less than one, suggesting that D-13 ♂ ♂ were less competitive in nature, although equally competitive under laboratory conditions.

Genetic analysis was performed on two polymorphic enzyme systems in the malaria vector, Anopheles culicifacies Giles. The data indicate that both enzymes, octanol dehydrogenase and acid phosphatase, are controlled by autosomal loci but that these two loci are not linked. The three expected linkage groups in this mosquito have now been identified: linkage group I contains sex and rose-eye; linkage group II contains Odh; and linkage group III contains Acph.

The problem of environmental pollution and the advent of insecticidal resistance among mosquitoes and other pest insects have stimulated considerable interest in the possibility of mosquito control with genetic techniques. The goal of these methods is suppression or eradication of the pest population by introduction of genetic factors which would impose a load on the target population. However, aside from the preliminary work of a few workers (Craig and VandeHey 1962, Kitzmiller et al. 1967, Sakai and Baker 1972) little is known of the genetic variability present in wild populations. Thus it would appear desirable to assess the variability within wild populations before any attempt at genetic control is undertaken.

A survey of alcohol dehydrogenase (Adh) in Culex tritaeniorhynchus Giles has uncovered five electrophoretic variants among laboratory strains. Detailed genetic analysis revealed that these variants are inherited as codominant alleles at a single locus. The Adh locus has been assigned to linkage group III between s and cl. A survey of a natural population from Lahore, Pakistan, revealed the presence of four of the five variants and suggests the possibility of using this enzyme polymorphism to monitor a release programme. Substrate specificity tests suggest that this enzyme can utilize almost any aliphatic primary alcohol as a substrate.

The chromosome complements of the following 15 species of culicine mosquitoes were studied and illustrated: Aedes (Christophersiomyia) thomsoni (Theobald), Aedes (Stegomyia) albopictus (Skuse), Aedes (Stegomyia) aegypti (Linnaeus), Armigeres (Armigeres) subalbatus (Coquillett), Culex (Lutzia) fuscanus Wiedemann, Culex (Lutzia) raptor (Edwards), Culex (Culex) fuscocephala Theobald, Culex (Culex) pipiens fatigans Wiedemann, Culex (Culex) annulus Theobald, Culex (Culex) pseudovishnui Colless, Culex (Culex) tritaeniorhynchus Giles, Culex (Culex) sitiens Wiedemann, Culex (Culex) neolitoralis Bram, Culex (Culex) bitaeniorhynchus Giles, and Culex (Culex) gelidus Theobald. The chromosomes of 11 of these species had not previously been studied, and the subgenera Christophersiomyia and Lutzia were examined for the first time. The diploid chromosome number for all species examined was 6. No heteromorphic chromosomes were found in tissues from testis or ovary. While the karyotypes of 12 of these species were in conformity to previous work, i.e., chromosome 1 being considerably shorter than chromosome 2 and 3 with chromosome 2 approximating chromosome 3, new karyotypes for 3 species, C. (L.) fuscanus, C. (L.) raptor and C. (C.) gelidus , were described in which chromosome 2 is considerably shorter and approximates chromosome 1.

A standard salivary chromosome map is presented for Anopheles vestitipennis, based upon a population collected in the state of Vera Cruz, Mexico. It is proposed that this serves as the “standard” map for this species. Certain similarities of banding pattern, particularly at the ends of the autosomes, are evident between vestitipennis and the Holarctic Maculipennis species.

The salivary gland chromosome map of Anopheles hectoris is described and figured. It is proposed that this map be considered the standard for this species. The hectoris chromosomes show a close relationship to those of Anopheles pseudopunctipennis pseudopunctipennis.

A new method of electromagnetic sounding in resistive electrical environments has been developed for use in lunar exploration. It is applicable to the study of terrestrial glaciers and ice sheets. A horizontal electric dipole antenna on the ground is used to transmit power at frequencies of 1, 2, 4, 8, 16 and 32 MHz. A set of orthogonal receiving coils is mounted on a vehicle which traverses away from the transmitter. Field strength is recorded as a function of distance. Waves which travel above the surface interfere with waves from the subsurface, generating interference patterns which can be used to determine the dielectric constant, the loss tangent, and depth to reflecting horizons.The technique was tested on the Athabasca Glacier in western Canada. At 1, 2 and 4 MHz the ice was found to have a dielectric constant of about 3.3, a loss tangent (tan δ) which is roughly inversely proportional to frequency giving values of f tan δ in the range 0.25 to 0.35 (where f is in MHz). These values correspond well with the known properties of ice near 0° C, which is a temperature typical of temperate glaciers. It has been possible to determine the depth of the ice but results are not always consistent with previous seismic and gravity surveys and with drilling. At frequencies of 16 and 32 MHz, scattering is the dominant feature of the results. At 8 MHz there is a transition from clear-cut interference patterns to the scattering patterns. From these findings, we suggest that the Athabasca Glacier has a large number of dielectric scatterers with dimensions less than about 35 m, probably due in large part to crevasses.

The sterilities of stocks with chromosomal aberrations were enhanced by re-irradiation. Males heterozygous for two independent aberrations were synthesized and their sterilities determined. The possible advantages of the double heterozygote males over either completely sterile males or those heterozygous for only one aberrational complex are discussed. Recently the possibility of using the semisterility associated with reciprocal translocations to control mosauitoes of medical importance has stimulated a considerable amount of resiarch in the experiGental induction of chromosomal aberrations (Laven, 1969; Bhalla, 1970; McDonald and Rai, 1970; Rai, McDonald and Asman, 1970; Baker, Sakai and Mian, 1971b; Sakai, Baker and Mian, 197 1). Escludina instances of non-disjunction between homologous centromeres and assuGng chat duplication-deficiency gameres lead to che formation of zygotic comh~nations which are lethal, the expected sterility of an individual heterozygnus for a single reciprocal translocation js 50%; 75% for a translocation heterozygote involving three non-homologous chromosnmes. Thus rhe maximum sterility expected with translocations in imects arch as mosquitncs, which have three pairs of chromosomes, appears rather Im in comparison -\kith rhe sterilibr employed in the sterile male techniqne. This paper reports the results if a series of ex-pcrimenrs wirh the mosquito, Czl/ex tritn#rimhy?~cb~s, of an attempt to enhance the sterility beyond the expected maximum.