The study included only samples from females to avoid complications associated with DUI, as mtDNA genome-specific primers such as those used for Mytilus are not available for the genus Perna. This genetic pattern was interpreted as being the result of highly asymmetrical levels of larval dispersal between coastal habitats and bays. While there was no structure between coastal regions, sites within bays were not only genetically distinct from those on the open coast, but also from each other. A genetic barrier for M-mtDNA exchange (possibly linked to DUI) was considered to be a more likely explanation for the observed pattern than gender-specific differences in larval dispersal capability.Ī recent study comparing genetic structure in the brown mussel ( Perna perna) between several South African coastal sites and bays identified a surprisingly large amount of mtDNA-based genetic structure at this relatively small geographic scale (10-100s km). edulis, with genetic interchange being evident for F-mtDNA but not for M-mtDNA. Levels of trans-Atlantic gene flow differ for the two genomes of M. Males have both a male (M-mtDNA) and a female (F-mtDNA) mitochondrial genome, whereas females only have a female genome. The family Mytilidae includes 33 genera and in five of these, including Mytilus, doubly uniparental inheritance (DUI ) has been identified. Nonetheless, sex-specific differences in genetic structure were found in the marine mussel Mytilus edulis, despite the fact that it has microscopic larvae with extremely limited swimming abilities and presumably passive dispersal. Numerous studies have used maternally-inherited mitochondrial DNA (mtDNA) in conjunction with biparentally-inherited nuclear DNA markers, and discrepancies between results from the two types of markers have been interpreted as the result of sex-specific differences in dispersal.įor marine invertebrates, sex-biased dispersal is not usually considered because dispersal in most of these species takes place either by means of planktonic larvae or by association of adults or egg masses with floating objects. ![]() Genetic markers with sex-specific inheritance have long been used to study differences in genetic structure between males and females. Higher survival rates of males in non-native habitats can erase the genetic structure present in their mothers within a single generation. Third, even though mtDNA is typically used to study historical demographic processes, it also contains information about contemporary processes. Second, the fact that sex-specific differences were found in a passively dispersing species in which sex-biased dispersal is unlikely highlights the fact that significant genetic structure is not necessarily a function of low dispersal potential or physical barriers. For that reason, using it to identify sex-specific differences in genetic structure by contrasting it with biparentally-inherited markers is problematic. First, even when mtDNA is inherited exclusively in the female line, it also contains information about males. Our results have three important implications for the interpretation of population genetic data. The observed pattern most likely stems from females being more vulnerable to selection in habitats from which they did not originate, which also manifests itself in a male-biased sex ratio. This is the first study to report sex-specific differences in genetic structure based on matrilineally-inherited mtDNA in a passively dispersing species that lacks social structure or sexual dimorphism. ![]() By treating males and females as different populations, we identified significant genetic structure on the basis of mtDNA data in the females only. ![]() We sampled the intertidal rocky shore mussel Perna perna in a South African bay and along the nearby open coast, and sequenced maternally-inherited mtDNA (there is no evidence for paternally-inherited mtDNA in this species) and a biparentally-inherited marker. ![]() When genetic structure is identified using mitochondrial DNA (mtDNA), but no structure is identified using biparentally-inherited nuclear DNA, the discordance is often attributed to differences in dispersal potential between the sexes.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |