Genetics of sexual Ostracoda from a low Arctic site

• Published in: Journal of Evolutionary Biology
• Main Authors: Havel, John E., Hebert, Paul D. N., Delorme, L. Denis
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 1990
• Subjects: Ecology, Evolution, Behavior and Systematics; Arctic
• Online Access: http://dx.doi.org/10.1046/j.1420-9101.1990.3010065.x; https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1046%2Fj.1420-9101.1990.3010065.x; https://onlinelibrary.wiley.com/doi/pdf/10.1046/j.1420-9101.1990.3010065.x

Abstract Members of the crustacean subclass Ostracoda show a high incidence of transitions from sexual to asexual reproduction. The cause of these shifts remains uncertain, perhaps because there have been few genetic studies on the group. The present study examined sex ratios and allozyme variation in 7 sexual species of ostracodes from ponds at a low Arctic site. Sex ratios in most species were strongly female‐biased. Detailed study of Cyprinotus glaucus indicated that sex ratios were heterogeneous among populations, but stable during juvenile‐adult development. Among 6 species, the proportion of polymorphic loci ranged from 0–33 %, and individual heterozygosities 0–14 %. Genotypic frequencies at polymorphic loci conformed to Hardy‐Weinberg expectations in all species, but gene frequency differences among local populations of C. glaucus suggest restricted gene flow for this passively‐dispersed species. Averaged over 5 species, approximately 27 % of the polymorphic loci were sex‐linked. Linkage relationships were variable, with an individual locus being sex‐linked in some species and autosomal in others.