Datasets S1 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。因纽特人的先民是首个将犬拉雪橇运输技术大规模引入美洲的人群，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，还是向该区域引入了全新的犬类种群。为验证上述假说，我们共获取了跨越4500余年的922份北美北极犬类与狼样本的颅骨及牙齿标本的线粒体DNA（mitochondrial DNA）与几何形态测量学（geometric morphometric）数据。分析结果显示，年代距今2000年的因纽特人遗址出土的犬类，其形态学与遗传学特征均有别于早期的古因纽特犬；同时我们在东西伯利亚与阿拉斯加地区发现了一个全新的线粒体DNA进化支（clade）。尽管考古出土的北极犬与现代北极犬类存在表型差异，但这类因纽特犬的遗传学遗产至今仍存续于现代北极雪橇犬种群中。综合来看，我们的研究数据表明，因纽特犬源自一次独立于古因纽特犬的、发生在欧洲人接触美洲前的二次犬类迁徙事件，且这类犬极有可能在距今约1000年左右助力了因纽特人向北美北极地区的扩张。