Genetic Diversity And Multiple Paternity Of Western Mosquito Fish (Gambusia Affinis) In China

Western Mosquito fish(Gambusia affinis),a famous invasive species,was introduced into mainland China since the 1920 s.After a century of reproduction and spread,it has now been widely distributed in the main lakes and rivers in China.Genetic diversity of G.affinis is important genetic basis for its successful invasion,while the multiple mating of female makes a significant contribution in the successful invasion and spread of Mosquito fish.We used eight high polymorphic microsatellite markers to assess the genetic diversity information of 6 G.affinis populations in the wild.Moreover,we also explored geographic and potential temporal variations in patterns of multiple paternity in G.affinis.The main results are as follows:1.All six populations deviated from Hardy-Weinberg equilibrium.According to bottleneck analyses under three microsatellite evolution models,most of the populations underwent recent genetic bottlenecks.The standard population genetic parameters indicated abundant genetic diversity of six populations.2.Multiple paternity is a widespread reproductive strategy in G.affinis.I found a significant difference in number of sires per clutch among studied populations,which might be caused by various environmental factors,e.g.climatic factors,sex ratio in populations,and the presence of predators,and different female fecundity among populations.3.There are temporal variations in patterns of multiple paternity,frequencies and number of sires per clutch,across the breeding season of G.affinis.The temporal variations could be mainly ascribed to female fecundity.In summary,I found the high-level genetic diversity and the prevalence of multiple paternity in G.affinis populations in this study,which implies the certain contribution of multiple paternity reproductive strategy in maintain the genetic diversity of invasive G.affinis.In addition,the notable temporal and geographic variations in patterns of multiple paternity indicates effects of environmental factors on multiple paternity in G.affinis.