Datasets S3 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（Inuit）的祖先率先将狗拉雪橇（dog sledge）运输技术大规模引入美洲大陆，但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类种群，这一问题至今尚无定论。为验证上述假说，我们对时间跨度超过4500年的共计922具北美北极犬与狼标本采集了线粒体DNA（mitochondrial DNA）与几何形态测量学（geometric morphometric）数据，分析对象涵盖颅骨与齿部结构。分析结果显示，出土于距今2000 BP的因纽特遗址的犬类，其形态学与遗传学特征均与更早的古因纽特犬存在显著区别；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进化枝（mitochondrial clade）。尽管考古出土的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谱系至今仍留存于现代北极雪橇犬体内。综合来看，我们的研究数据表明，因纽特犬源自与古因纽特犬截然不同的、接触前的二次犬类迁徙事件，且极有可能在距今约1000 BP时助力因纽特人向北美北极地区扩张。