关键词: 东北马鹿, mtDNA, 微卫星, 遗传多样性, 粪便DNA

Abstract: As an endangered species listed in the Class Ⅱ protected species of the national government of China, wapiti (Cervus canadensis xanthopygus) in northeast China has been experiencing population contraction and gene flow block between populations in recent years, and it is hard to find its traces in many areas. It is an urgent need to further evaluate the genetic changes of the population, especially the genetic diversity and inbreeding decline, so as to enhance the pertinence of conservation and management. In this study, 409 suspected fecal samples of wapiti were collected from six key research areas in Daxing'an, Xiaoxing'an, and Changbai Mountains. Firstly, species identification was carried out based on mtDNA Cyt b gene sequencing technology, and the positive samples were supplied for further individual identification by microsatellite technology. Finally, 172 wapiti individuals were identified from the 409 fecal samples. The results showed that there were 14 variation sites and 11 haplotypes in the Cyt b sequence of wapiti. In the populations, the haplotype diversity and nucleotide diversity of Cyt b gene were 0.849 (0.105-0.732) and 0.678% (0.099%-0.775%), respectively. Based on 10 microsatellite loci, we found that the mean number of alleles was 5.7 (5.2-7.2), the effective number of alleles was 3.3 (2.5-4.1), the average observed heterozygosity was 0.687 (0.644-0.725), the average expected heterozygosity was 0.619 (0.564-0.689), and the inbreeding coefficient was -0.113 (-0.160 to-0.037) in the populations. The results showed that the genetic diversity was at a medium level for populations, among which the Shuanghe and Tieli populations were the highest, followed by the Gaogestai and Huangnihe populations, and the Fangzheng and Muling populations were the lowest. The population decline and isolation of the distribution area affected the genetic diversity pattern of the six local populations. The high proportion of rare haplotypes and alleles suggested a risk of decreasing genetic diversity in the future. The Gaogestai and Huangnihe populations displayed significant differences in haplotype diversity and nucleotide diversity, which may be the result of rapid growth after the population decline. The negative inbreeding coefficients of populations showed no risk of inbreeding. It is suggested that individuals with rare haplotypes and alleles should be key targets in monitoring and protection. Additionally, promoting exchanges of individuals with nearby populations and releasing artificially bred populations in the field at the appropriate time may improve the gene exchange between individuals and accelerate population restoration.

Key words: Cervus canadensis xanthopygus, mtDNA, Microsatellite, Genetic diversity, Fecal DNA