Exploring The Genetic Differentiation Of East Asian Wild Boar (Sus Scrofa) Population Based On Nuclear Gene Variation

The wild boar Sus scrofa has the widest geographical range of all ungulates and one of the widest of all terrestrial mammals.It was originated in South-East Asia,spreading in the Asian continent,and followed by its colonization of Europe and North Africa.Many studies had shown that the genetic structure of wild boar in Europe was highly influenced by past climatic events,especially those related to the LGM.However,the phylogeographic structure of wild boar populations in the East Asia has not yet been thoroughly studied.In this study,five nuclear genes were used to explore the genetic diversity,genetic structure and gene flow of wild boar in East Asia.The main results were as follows:1.Total of 309 individuals was sampled from 66 locations which were defined as 12 populations.High levels of haplotype diversity was found for the 5 nuclear genes(0.99 ± 0.01)in the East Asia wildboar,and nucleotide diversity was relatively low(0.004 ± 0.002).The populations in Nanling Moutain,Qinling Mountain,the middle and lower reaches of the Yangtze River and Daba Mountain have the relatively high haplotype and nucleotide diversity,the next were in Hainan and West Sichuan region,and the lowest in the Taihang Moutain and North China region.Genetic divergence was not simply related to geographical distance,and a clear south-north decreasing gradient of diversity was observed,with maximum levels in putative glacial refugia,and the southern remnant populations experienced postglacial expansions towards northern areas.2.The pairwiseFst between the populations ranged from 0.000 to 0.500 with a mean of 0.038.The genetic divergence was significantly between Qinling Moutain populations and others except for the North China and Taihang Mountain population.The results both form the Bayesian phylogenetic trees which constructed for the haplotypes,and the Bayesian-clustering analysis show that there was no significant phylogenetic structure among populations.3.Gene flow analysis indicated the historically gene flow was large(Nfem>480)among populations.The strong gene flow among the populations in the middle and lower reaches of the Yangtze River suggest that large rivers did not affect gene flow between the two sides.To a certain extent,this pattern may be explained by the behavioral traits of wild boar,as it is characterized by specific habitats with strong dispersal ability and environmental adaptability.And such a high dispersal capacity tends to promote gene flow from neighboring populations and thus erodes patterns of genetic divergence.