Wang Weiran, Yao Meng
School of Life Sciences, Peking University, Beijing, China.
Beijing National Day School, Beijing, China.
Am J Primatol. 2017 May;79(5). doi: 10.1002/ajp.22635. Epub 2017 Jan 18.
Dispersal is a critically important life history trait of social organisms that has a major impact on the population genetic structure and social relationships within groups. Primates exhibit highly diversified dispersal and philopatry patterns, but knowledge of these patterns is difficult to obtain and usually limited to observations of a small number of focal social groups or individuals. Here, we investigated the dispersal pattern of a critically endangered colobine monkey, the white-headed langur (Trachypithecus leucocephalus), using molecular approaches, and sex-specific population genetic structure analyses at fine geographical scales. We non-invasively collected 403 fecal samples from 41 social groups across 90% of the langur's range in Fusui (FS) and Chongzuo (CZ) in southwestern Guangxi Province, China. We identified 214 unique individuals from the samples by genotyping 15 polymorphic autosomal microsatellite loci, a sex-specific marker, and sequencing the mitochondrial DNA (mtDNA) hypervariable region I (HVRI). We found higher intragroup than intergroup genetic relatedness in males and females in both populations. A significant positive correlation between genetic distance and geographical distance, that is a pattern of isolation-by-distance, was detected in females from the FS population, but not in males. Spatial autocorrelation analyses revealed high within-group relatedness in both sexes and populations, as well as an additional positive correlation at the 0.5-km distance class in females from the FS population. Furthermore, we inferred first-generation migrants using genetic assignment tests. Our results suggest that male T. leucocephalus disperse at random distances within habitat areas, whereas dispersal of females may mainly occur among adjacent groups near their home site. Our study provides the first genetic evidence for sex-biased dispersal in T. leucocephalus, which has important management and conservation implications for the species.
扩散是社会性生物至关重要的生活史特征，对种群遗传结构和群体内的社会关系有重大影响。灵长类动物表现出高度多样化的扩散和留居模式，但这些模式的相关知识难以获取，通常仅限于对少数重点社会群体或个体的观察。在此，我们采用分子方法，在精细地理尺度上对极度濒危的叶猴——白头叶猴（Trachypithecus leucocephalus）的扩散模式以及性别特异性种群遗传结构进行了分析。我们在中国广西西南部扶绥（FS）和崇左（CZ）对白头叶猴分布范围90%的41个社会群体进行了非侵入性粪便样本采集，共收集到403份样本。通过对15个多态性常染色体微卫星位点、一个性别特异性标记进行基因分型，并对线粒体DNA（mtDNA）高变区I（HVRI）进行测序，我们从样本中鉴定出214个独特个体。我们发现，两个种群的雄性和雌性个体组内遗传相关性均高于组间。在FS种群的雌性个体中检测到遗传距离与地理距离之间存在显著正相关，即距离隔离模式，但在雄性个体中未检测到。空间自相关分析显示，两个种群的雌雄个体组内相关性都很高，并且FS种群的雌性个体在0.5公里距离级别上还存在额外的正相关。此外，我们通过遗传分配测试推断出第一代移民。我们的研究结果表明，白头叶猴雄性在栖息地内随机距离扩散，而雌性扩散可能主要发生在其出生地附近的相邻群体之间。我们的研究首次为白头叶猴的性别偏向扩散提供了遗传证据，这对该物种的管理和保护具有重要意义。
