Genetic Differentiation And Genetic Diversity Of Rhesus Macaques In Sichuan Base On Microsatellite Markers

The macaque(Macaca mulatta)is a Grade II protected animal and one of the most widely distributed non-human primate.The Sichuan of China is currently the most populated area of wild macaques distribution,as understanding of their genetic differentiation among different populations is pivotal for studying their historical evolution.However,their genetic diversity is mainly marked by maternal inherited mitochondrial molecules,but there are limitations in analyzing the comprehensive data on nuclear genetic information of macaque population from Sichuan.For this purpose,we collected blood and fecal samples of 328 wild macaques from 18 geographic populations in Sichuan,and analyzed their nuclear data to know the overall genetic structure,genetic diversity and population history by nested PCR with 10 microsatellite loci and capillary electrophoresis assays.The main results are as follows:(1)Based on genetic structure analysis,the M.m.vestita of the Gongbujiangda population was used as a reference,wild macaques of Sichuan were divided into two clusters;Western,central and eastern populations were clustered into one group,belonging to the M.m.lasiotus.While southern and northeastern populations were clustered into another group and were more closely related to the M.m.vestita.(2)Based on phylogenetic relationship analysis,the Jiangjin and Fengjie populations were clustered into one group with the Yajiang population.Whereas,the Gulin and Nanjiang populations were clustered into other group with the Daofu population,results indicated that macaques in eastern Sichuan were closely related with the Yajiang population,and that genetic exchange events were occurred among the Gulin,Nanjiang,and Daofu populations.The five macaques populations in the Yajiang region were belonged to two branches,the M.m.vestita and the M.m.lasiotus.There were overlapping ecological niches and interspersed distributions of the two subspecies in the Yajiang region.Further phylogenetic analysis by sex revealed that male macaques were not clustered according to the geographic location whereas males from the same geographic population cross-clustered in different branches.It suggested that males have a stronger dispersal ability than females,it leads to frequent gene flow in Sichuan macaques.(3)Based on genetic diversity and population history analysis,the average number of alleles(Na)of the 18 geographic populations were 11.722,the average number of effective alleles(Ne)was 7.339,the average observed heterozygosity(Ho)was 0.529,the average expected heterozygosity(He)were 0.827,and the average polymorphic information content(PIC)of the 10 microsatellite loci was 0.927.This indicates that wild Sichuan macaque populations have moderately high levels of genetic diversity,but the Hardy-Weinberg equilibrium detection and fixation indices suggest that inbreeding exists within Sichuan macaque populations and that Baiyu,Seda,Heshui,Fengjie,Jiangjin,Nanjiang,and Gulin populations may have experienced genetic bottleneck.The present study on genetic differentiation and genetic diversity of Sichuan macaques using microsatellite markers showed that macaques from various geographic populations have relatively frequent genetic exchange,less differentiation among populations,and high levels of genetic diversity,but also inbreeding and genetic bottlenecks.It provides some basic genetic information for the conservation and utilization of wild macaques in Sichuan.