关键词: 藏羚, 粪便DNA, 交配群, 亲缘关系, 遗传多样性

Abstract: Tibetan antelope (Pantholops hodgsonii), an endemic species of the Qinghai-Tibet Plateau, exhibits group living and sexual segregation behaviors. Outside the rutting season, male and female Tibetan antelope live separately. In this study, a total of 188 fresh fecal samples were collected from 32 groups of Tibetan antelope in the Kekexili region of the Sanjiangyuan National Park in late December 2021. Genetic diversity analysis and parentage testing were conducted using ten highly polymorphic microsatellite loci. The findings revealed that out of the 188 fresh fecal samples, genetic identification confirmed the presence of 145 individual Tibetan antelope. Among them, ten Tibetan antelope individuals (eight females and two males) sequentially appeared in different groups over time. Field observations indicated three mechanisms for recombination among mating groups including group dissolution, male departures or arrivals to/from existing groups, and female departures or arrivals to/from existing groups. Notably, there was considerable genetic differentiation between individuals that changed groups compared to those remaining within their original group composition. Male Tibetan antelopes moved to groups with a higher proportion of females than their previous ones, thereby increasing their potential for acquiring more mates and enhancing opportunities for gene inheritance. The average number of alleles across the ten microsatellite loci was 16. 1, with an average polymorphic information content of 0. 766. Observed heterozygosity (Ho) ranged from 0. 607 to 0. 993 with a mean value of 0. 819. Expected heterozygosity (He) ranged from 0. 575 to 0. 930 with a mean value of 0. 798. These results indicated a high level of genetic diversity within the Tibetan antelope population. At the group level, out of the total parent-child relationships observed (n = 32), fourteen (43. 75%) occurred within the same group, predominantly in mother-daughter relationships (71. 43 %), while only four (28. 57%) involved males (mother-son/father-daughter/father-son). By comparing the average coefficients of relatedness between groups with or without males, our findings suggested that the presence or absence of males had minimal impact on genetic relatedness among group members, indicating that closest genetic relationships within mating groups were primarily among females. Our findings demonstrated that low levels of inbreeding in Tibetan antelope populations and highlight female-female associations as key drivers for forming stable groups and facilitating communication and transmission of migration information due to their higher relatedness compared to males. These results provided scientific evidence supporting further validation of the collective memory conjecture regarding Tibetan antelope migration.

Key words: Tibetan antelope, Fecal DNA, Mating group, Parentage testing, Genetic diversity