School of Ecology and Nature Conservation, Beijing Forestry University, Beijing, China.
School of Biological Sciences, The University of Hong Kong, Hong Kong SAR, China.
Integr Zool. 2023 May;18(3):453-468. doi: 10.1111/1749-4877.12680. Epub 2022 Oct 10.
A herd of 15 Chinese elephants attracted international attention during their 2021 northward trek, motivating the government to propose establishment of an Asian elephant national park. However, planning is hampered by a lack of genetic information on the remaining populations in China. We collected DNA from 497 dung samples from all 5 populations encompassing the entire range of elephants in China and used mitochondrial and microsatellite markers to investigate their genetic and demographic structure. We identified 237 unique genotypes (153 females, 84 males), representing 81% of the known population. However, the effective population size was small (28, range 25-32). Historic demographic contraction appeared to account for low haplotype diversity (H = 0.235), but moderate nucleotide and nuclear diversity (π = 0.6%, H = 0.55) was attributable to post-bottleneck recovery involving recent population expansion plus historical gene exchange with elephants in Myanmar, Lao PDR, and Vietnam. The 5 populations fell into 3 clusters, with Nangunhe elephants differing consistently from the other 4 populations (F = 0.23); elephants from Mengyang, Simao, and Jiangcheng belonged to a single population (henceforth, MSJ), and differed from the Shangyong population (F = 0.11). Interpopulation genetic variation reflected isolation by distance and female-biased dispersal. Chinese elephants should be managed as 2 distinct units: Nangunhe and another combining Shangyong and MSJ; their long-term viability will require restoring gene flow between Shangyong and MSJ, and between elephants in China and neighboring countries. Our results have the potential to inform conservation planning for an iconic megafaunal species.
一群 15 头中国大象在 2021 年的北移中引起了国际关注，促使政府提出建立亚洲象国家公园。然而，由于中国剩余种群缺乏遗传信息，规划受到了阻碍。我们从中国境内所有 5 个大象种群的 497 份粪便样本中采集了 DNA，并使用线粒体和微卫星标记来研究它们的遗传和种群结构。我们鉴定出了 237 个独特的基因型（153 头雌性，84 头雄性），代表了已知种群的 81%。然而，有效种群规模较小（28，范围 25-32）。历史上的种群收缩似乎导致了低单倍型多样性（H = 0.235），但中等核苷酸和核多样性（π = 0.6%，H = 0.55）归因于瓶颈后恢复，包括最近的种群扩张以及与缅甸、老挝和越南大象的历史基因交流。这 5 个种群分为 3 个聚类，其中弄岗象种与其他 4 个种群明显不同（F = 0.23）；来自勐养、思茅和江城的大象属于一个种群（以下简称 MSJ），与上允种群不同（F = 0.11）。种群间的遗传变异反映了隔离距离和雌性扩散的偏倚。中国大象应该作为 2 个不同的单位进行管理：弄岗和另一个由上允和 MSJ 组成的单位；为了确保它们的长期生存能力，需要恢复上允和 MSJ 之间以及中国和邻国大象之间的基因流动。我们的研究结果有可能为保护这种标志性的大型动物物种提供信息。
