基于微卫星的欧亚水獭个体识别和遗传多样性OACSTPCD

Population size and genetic diversity are important basic information for threatened species conservation.As a Class Ⅱ protected animal,Eurasian otter(Lutra lutra)was once widely distributed in China,but has experienced severe population decline and range shrinkage over the 20th century.However,only a few studies have been conducted on Eur-asian otters in China.Basic research such as population surveys and genetic diversity studies are urgently needed.We collected 270 otter spraints for DNA extraction during 2019-2020 in Yushu City,Qinghai Province and Qingchuan Coun-ty,Guangyuan City,Sichuan Province.We used 9 microsatellite loci and the SRY gene to genotype individuals and iden-tify sex.Then we estimated the sizes of the two populations based on individual identification and noninvasive capture-recapture method(Capwire).We also assessed their genetic diversity based on the nine microsatellite markers.We suc-cessfully genotyped 67 spraints(24.8％)with 7-9 microsatellites and identified 40 otter individuals.Among them,10 were from Yushu and 30 were from Qingchuan,with a sex ratio of 4F/5M and 15F/14M respectively.Sex identification failed for two individuals.The estimated population of otters within our study area was 13(95％CI:7-21)in Yushu City and 75(95％CI:59-133)in Qingchuan County.The average observed heterozygosity(HO)and expected heterozy-gosity(HE)of the Yushu population were 0.680 and 0.611,while those of the Qingchuan population were 0.664 and 0.658,revealing a moderate genetic diversity.Otters in Yushu and Qingchuan have been differentiated significantly(FST=0.238)and no significant inbreeding was found in both populations(FIS:Yushu-0.121,Qingchuan-0.010).As the first study estimating population size and genetic diversity of Eurasian otters based on fecal DNA in Chinese main-land,our work provides important basic information for otter conservation in China.