Datasets S4 from Specialized sledge dogs accompanied Inuit dispersal across the North American Arctic

Domestic dogs have been central to life in the North American Arctic for millennia. The ancestors of the Inuit were the first to introduce the widespread usage of dog sledge transportation technology to the Americas, but whether the Inuit adopted local Paleo-Inuit dogs or introduced a new dog population to the region remains unknown. To test these hypotheses, we generated mitochondrial DNA and geometric morphometric data of skull and dental elements from a total of 922 North American Arctic dogs and wolves spanning over 4500 years. Our analyses revealed that dogs from Inuit sites dating from 2000 BP possess morphological and genetic signatures that distinguish them from earlier Paleo-Inuit dogs, and identified a novel mitochondrial clade in eastern Siberia and Alaska. The genetic legacy of these Inuit dogs survives today in modern Arctic sledge dogs despite phenotypic differences between archaeological and modern Arctic dogs. Together, our data reveal that Inuit dogs derive from a secondary pre-contact migration of dogs distinct from Paleo-Inuit dogs, and most likely aided the Inuit expansion across the North American Arctic beginning around 1000 BP.

数千年来，家犬一直是北美北极地区人类生活的核心组成部分。因纽特人的先祖是首个将犬拉雪橇运输技术大规模引入美洲的群体，但目前仍不清楚因纽特人究竟是接纳了当地的古因纽特犬（Paleo-Inuit dogs），还是向该区域引入了全新的犬只种群。为验证上述假说，我们针对共计922份跨度超4500年的北美北极犬与狼的头骨及牙齿标本，采集了线粒体DNA（mitochondrial DNA）与几何形态测量学（geometric morphometric）数据。分析结果显示，年代可追溯至距今2000年（Before Present, BP）的因纽特遗址出土犬只，其形态学与遗传学特征均有别于早期古因纽特犬；同时我们在东西伯利亚与阿拉斯加地区鉴定出一个全新的线粒体进化枝（mitochondrial clade）。尽管考古出土北极犬与现代北极犬存在表型差异，但这些因纽特犬的遗传遗产至今仍留存于现代北极拉雪橇犬的种群中。综合来看，本研究数据表明，因纽特犬源自与古因纽特犬截然不同的、一场发生在对外接触前的二次犬只迁徙事件，且这批犬只极有可能助力因纽特人于距今约1000年（Before Present, BP）前后向北美北极地区完成扩张。