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Abstract Background The swimming crab Portunus trituberculatus is one of the most commonly farmed crustaceans in China. As one of the most widely known and high-value edible crabs, it crab supports large crab fishery and aquaculture in China. Only large and sexually mature crabs can provide the greatest economic benefits, suggesting the considerable effect of reproductive system development on fishery. Studies are rarely conducted on the molecular regulatory mechanism underlying the development of the reproductive system during the mating embrace stage in this species. In this study, we used high-throughput sequencing to sequence all transcriptomes of the P. trituberculatus reproductive system. Results Transcriptome sequencing of the reproductive system produced 81,688,878 raw reads (38,801,152 and 42,887,726 reads from female and male crabs, respectively). Low-quality (quality

Abstract: Trypanosoma cruzi, the agent of Chagas disease, is usually subdivided into six discrete typing units (DTUs), TcI to TcVI, among which TcI and TcV are most common in human infections in Bolivia. Multilocus microsatellite typing (MLMT) was selected to further explore the structure of the natural populations belonging to these DTUs. The analysis showed that microsatellite clustering does not fully match the six DTUs, but it is relevant for the within DTUs analyses. Population genetics analysis was conducted on 11 relevant subsamples of stocks from Bolivia and Peru, belonging to TcI (6) and TcV (5), defined by four criterions: DTU, vector species, geographic origin, and date of isolation. Most TcV strains presented the same multilocus genotype over all subsamples with the puzzling characteristic that five loci were heterozygous and the other five homozygous. In TcI, four clusters were defined according to the vector species. Most of them appeared in agreement with clonal propagation (stocks isolated from Triatoma infestans and Triatoma sordida), while a few highly homozygous stocks (e.g. those isolated from Rhodnius stali) suggested that scarce sex events can occur. The poor role played by spatio-temporal factors in describing the observed genetic diversity suggested that ecology, in particular as regard to host played a significant role. These results highlight the extreme heterogeneity of T. cruzi and suggest that further population genetics surveys will need to target the most possible precise spatio-temporal and ecological scales. [Copyright &y& Elsevier]

Important scientific findings frequently arise from serendipitous findings. Unfortunately, many scientists are not prepared to take advantage of unexpected results and to question established paradigms, and this prevents them from capitalizing on their good fortune. In this essay, I first explain how pure serendipity led us to discover unusual modes of reproduction such as clonal reproduction by males and a green-beard gene. Next, I argue that the reproductive systems of ants and other organisms are probably much more diverse than is generally appreciated. This leads me to advocate for a new ‘molecular naturalist’ approach to reproductive systems and a more ‘naturalistic’ approach in population and evolutionary genetics. Finally, I make two further points. The first is that our current funding and education systems tend to hinder originality and curiosity. The other is that the field of ecology and evolution, and more generally all of science, would benefit from a shift in values from scientific productivity to scientific creativity. A few suggestions are made to this effect. [ABSTRACT FROM AUTHOR]

Patterns of isozyme variation were examined in 17 populations of P. pusillus and P. berchtoldii, together with one population of P. trichoides taken for comparison. Both P. pusillus and P. berchtoldii displayed low levels of variation within populations associated with high levels of interpopulation differentiation. This pattern of partitioning of genetic variation within and between populations is attributed to the founder effect, frequent vegetative propagation by turions, dominant self-fertilization and limited seedling recruitment. The mechanism of pollen transfer was investigated in cultivation. Effective pollination takes place in air above the water surface (autogamy, geitonogamy, anemogamy), on the water surface (epihydrogamy) or below water surface (hydroautogamy). The species are self-compatible. The low level of infra-population variation together with rare occurrence of heterozygotes suggest that selfing is the most frequent mode of pollination, although the protogynous flowers may occasionally permit some cross-pollination. Unique enzyme markers were found for P. pusillus and P. berchtoldii, and also for the single population of P. trichoides. All multienzyme phenotypes were species-specific. Isozyme data support the separate position of P. pusillus and P. berchtoldii. UPGMA dendogram based on enzyme data of 133 plant samples revealed three distinct main enzymatic entities perfectly corresponding to the three morphologically defined species. [ABSTRACT FROM AUTHOR]

Competition among relatives can modify the genetic structure of plant populations; in turn, competitive outcomes can depend on the genetic relatedness of the individuals competing. The offspring from individual parents exhibit a continuum of genetic relatedness, depending on parental reproductive systems. Competition among relatives may have evolutionary significance as a selection pressure; sibling competition, for example, has been invoked to explain the evolution of sexual systems, seed packaging within fruits, seed dispersal dimorphisms, and germination behavior. Density-dependent fitness consequences of sibling competition have been documented in a population of the annual grass Sporobolus vaginiflorus. This species produces seeds matured in cleistogamous spikelets within leaf sheaths along tillers in autumn; when seeds along the tillers of a maternal parent (i.e. a sibship) germinate in situ the following spring in close proximity to one another, sibling competition results in a high-density zone centered around the original senescent parent. Both intra- and intersibship interactions can occur within a population. Although fitness is much reduced for siblings inside the zone of competition, potential seed rain and net primary productivity per unit area are significantly higher relative to outside the zone. This annual is functionally analogous to a perennial ramet producer with a phalanx growth strategy and the unit of selection may be the sibling group. It is not yet known whether sibling competition is a significant selection pressure in other species, but indirect evidence suggests it may be relatively widespread. [ABSTRACT FROM AUTHOR]