Lineage losses for man's best friend Dogs have been present in North America for at least 9000 years. To better understand how present-day breeds and populations reflect their introduction to the New World, Ní Leathlobhair et al. sequenced the mitochondrial and nuclear genomes of ancient dogs (see the Perspective by Goodman and Karlsson). The earliest New World dogs were not domesticated from North American wolves but likely originated from a Siberian ancestor. Furthermore, these lineages date back to a common ancestor that coincides with the first human migrations across Beringia. This lineage appears to have been mostly replaced by dogs introduced by Europeans, with the primary extant lineage remaining as a canine transmissible venereal tumor. Science, this issue p. 81; see also p. 27 Ancient North American dogs survive primarily as a canine transmissible venereal tumor. Dogs were present in the Americas before the arrival of European colonists, but the origin and fate of these precontact dogs are largely unknown. We sequenced 71 mitochondrial and 7 nuclear genomes from ancient North American and Siberian dogs from time frames spanning ~9000 years. Our analysis indicates that American dogs were not derived from North American wolves. Instead, American dogs form a monophyletic lineage that likely originated in Siberia and dispersed into the Americas alongside people. After the arrival of Europeans, native American dogs almost completely disappeared, leaving a minimal genetic legacy in modern dog populations. The closest detectable extant lineage to precontact American dogs is the canine transmissible venereal tumor, a contagious cancer clone derived from an individual dog that lived up to 8000 years ago.

中文翻译：

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美洲狗的进化史

人类最好的朋友狗的血统丧失在北美已经存在了至少 9000 年。为了更好地了解当今的品种和种群如何反映它们进入新世界的情况，Ní Leathlobhair 等人。对古代狗的线粒体和核基因组进行了测序（参见古德曼和卡尔森的观点）。最早的新世界狗不是由北美狼驯化的，而是可能起源于西伯利亚祖先。此外，这些谱系可以追溯到一个共同的祖先，该祖先与人类首次跨越白令海峡的迁徙相吻合。该谱系似乎已大部分被欧洲人引进的狗所取代，现存的主要谱系仍然是犬传染性性病肿瘤。科学，本期第 14 页。81；另见 p. 27 古代北美狗主要以犬传染性性病肿瘤的形式生存。在欧洲殖民者到来之前，狗就已经出现在美洲，但这些接触前的狗的起源和命运很大程度上未知。我们对来自古代北美和西伯利亚狗的 71 个线粒体和 7 个核基因组进行了测序，时间范围跨越约 9000 年。我们的分析表明，美国狗并非源自北美狼。相反，美国狗形成了一个单系谱系，很可能起源于西伯利亚，并与人类一起传播到美洲。欧洲人到来后，美洲本土狗几乎完全消失，在现代狗种群中留下了极少的遗传遗产。现存可检测到的与接触前的美国狗最接近的谱系是犬传染性性病肿瘤，这是一种源自一只生活在 8000 年前的狗个体的传染性癌症克隆。