Postcopulatory selection for dissimilar gametes maintains heterozygosity in the endangered North Atlantic right whale

Ecology and Evolution

T. R. Frasier²  R. M. Gillett³  P. K. Hamilton¹  M. W. Brown¹  S. D. Kraus¹ 

[1] John H. Prescott Marine Laboratory, New England Aquarium, Boston, Massachusetts, USA;Department of Biology and Forensic Sciences Program, Saint Mary's University, Halifax, Nova Scotia, Canada;Natural Resources DNA Profiling and Forensic Centre, Department of Biology, Trent University, 2140 East Bank Drive, Peterborough, Ontario, Canada

关键词: Genetic incompatibility;    genetic variation;    mate choice;    mate incompatibility;    right whale;   

DOI  :  10.1002/ece3.738

来源: Wiley

【 摘 要 】

Abstract

Although small populations are expected to lose genetic diversity through genetic drift and inbreeding, a number of mechanisms exist that could minimize this genetic decline. Examples include mate choice for unrelated mates and fertilization patterns biased toward genetically dissimilar gametes. Both processes have been widely documented, but the long-term implications have received little attention. Here, we combined over 25 years of field data with high-resolution genetic data to assess the long-term impacts of biased fertilization patterns in the endangered North Atlantic right whale. Offspring have higher levels of microsatellite heterozygosity than expected from this gene pool (effect size = 0.326, P < 0.011). This pattern is not due to precopulatory mate choice for genetically dissimilar mates (P < 0.600), but instead results from postcopulatory selection for gametes that are genetically dissimilar (effect size = 0.37, P < 0.003). The long-term implication is that heterozygosity has slowly increased in calves born throughout the study period, as opposed to the slight decline that was expected. Therefore, this mechanism represents a natural means through which small populations can mitigate the loss of genetic diversity over time.

【 授权许可】

CC BY   
© 2013 The Authors. Ecology and Evolution published by John Wiley & Sons Ltd.

Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.