Abstract

Tokelau is a remote archipelago of atolls in western Polynesia, located approximately 500 km north of Samoa. It is thought to have been settled as part of the Austronesian expansion(s). However, its exact role in this population dispersal is not completely understood. Here we describe the results of complete mitochondrial genome sequencing for both the current inhabitants and ancient individuals from the archipelago in addition to an assessment of Y-chromosome diversity among the present population. We find relatively little genetic diversity compared with other western Polynesian populations, most likely due to historically reported bottleneck events. However, the presence of rare mitochondrial lineages hints at prehistoric occupation by peoples from the northwest (e.g., Tuvalu and Micronesia). Ancient DNA data from Atafu, the northernmost Tokelauan atoll, is further consistent with abandonment and later resettlement of the island from a Samoan or Samoan-derived source population. Moreover, the ancient and modern mitogenomes also suggest links with other atoll populations in the western Pacific.

摘要

托克劳是波利尼西亚西部一个偏远的环礁群岛，位于萨摩亚以北约 500 公里处。它被认为是作为南岛扩张的一部分而定居的。然而，它在这种人口扩散中的确切作用尚不完全清楚。在这里，我们描述了当前居民和来自群岛的古代个体的完整线粒体基因组测序结果，以及对当前人口中 Y 染色体多样性的评估。与其他西波利尼西亚种群相比，我们发现遗传多样性相对较少，这很可能是由于历史上报道的瓶颈事件。然而，罕见线粒体谱系的存在暗示着西北地区（例如，图瓦卢和密克罗尼西亚）人民的史前占领。来自 Atafu 的古代 DNA 数据，最北端的托克劳环礁，进一步符合萨摩亚人或萨摩亚人源人口对该岛的遗弃和后来的重新安置。此外，古代和现代的有丝分裂基因组也暗示了与西太平洋其他环礁种群的联系。