Anas, is a genus of dabbling ducks and encompasses a considerable number of species, among which some are the progenitors of domestic ducks. However, the taxonomic position of the Anas genus remains uncertain because several of its species, initially categorized as Anas based on morphological characteristics, were subsequently reclassified and grouped with the South American genus Tachyeres, primarily based on analysis of their mitochondrial gene sequences. Here, we constructed a phylogenetic tree using nine of our recently assembled Anas genomes, two Tachyeres genomes, and one Cairina genome that are publicly available. The results showed that the Northern shoveler (Anas clypeata) and Baikal teal (Anas formosa) clustered with the other Anas species at the whole-genome level rather than with the Steamer ducks (genus Tachyeres). Therefore, we propose to restore the original classification of the Anas genus, which includes the Northern shoveler and Baikal teal species, 47 species in total. Moreover, our study unveiled extensive incomplete lineage sorting and an ancient introgression event from Tachyeres to Anas, which has led to notable phylogenetic incongruence within the Anas genome. This ancient introgression event not only supports the theory that Anas originated in South America but also that it played a significant role in shaping the evolutionary trajectory of Anas, including the domestic duck.

中文翻译：

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全基因组序列恢复了涉水鸭（Anas）的原始分类


鸭（Anas）是涉水鸭的一个属，包含相当多的物种，其中一些是家鸭的祖先。然而，鸭属的分类地位仍然不确定，因为它的几个物种最初根据形态特征被归类为鸭属，后来主要基于对其线粒体基因序列的分析，被重新分类并归入南美鹧鸪属。在这里，我们使用九个最近组装的Anas基因组、两个Tachyeres基因组和一个公开的Cairina基因组构建了一个系统发育树。结果表明，北铲鸭（Anas clypeata）和贝加尔鸭（Anas formosa）在全基因组水平上与其他鸭种聚集在一起，而不是与蒸鸭（Tachyeres属）聚集在一起。因此，我们建议恢复鸭属原来的分类，包括北铲鸭和贝加尔水鸭种，共47种。此外，我们的研究揭示了广泛的不完整谱系排序和从 Tachyeres 到 Anas 的古老基因渗入事件，这导致了 Anas 基因组内显着的系统发育不一致。这一古老的基因渗入事件不仅支持了阿纳斯起源于南美洲的理论，而且在塑造阿纳斯（包括家鸭）的进化轨迹中发挥了重要作用。