Hox genes are a remarkable example of conservation in animal development and their nested expression along the head‐to‐tail axis orchestrates embryonic patterning. Early in vertebrate history, two duplications led to the emergence of four Hox clusters (A‐D) and redundancy within paralog groups has been partially accommodated with gene losses. Here we conduct an inventory of squamate Hox genes using the genomes of 10 lizard and 7 snake species. Although the HoxC1 gene has been hypothesized to be lost in the amniote ancestor, we reveal that it is retained in lizards. In contrast, all snakes lack functional HoxC1 and ‐D12 genes. Varying levels of degradation suggest differences in the process of gene loss between the two genes. The vertebrate HoxC1 gene is prone to gene loss and its functional domains are more variable than those of other Hox1 genes. We describe for the first time the HoxC1 expression patterns in tetrapods. HoxC1 is broadly expressed during development in the diencephalon, the neural tube, dorsal root ganglia, and limb buds in two lizard species. Our study emphasizes the value of revisiting Hox gene repertoires by densely sampling taxonomic groups and its feasibility owing to growing sequence resources in evaluating gene repertoires across taxa.

中文翻译：

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蜥蜴拥有最完整的四足动物Hox基因谱系，尽管Hox簇中普遍存在结构变化。

Hox基因是动物发育中保护的一个杰出例子，它们沿头尾轴的嵌套表达可以协调胚胎的形态。在脊椎动物历史的早期，两次重复导致出现了四个Hox簇（A-D），旁系同源物组中的冗余已部分弥补了基因的损失。在这里，我们使用10个蜥蜴和7个蛇种的基因组进行了鳞状Hox基因清单。尽管已假定HoxC1基因在羊膜祖先中丢失，但我们发现它保留在蜥蜴中。相比之下，所有蛇都缺乏功能性的HoxC1和‐D12基因。降解水平的变化表明两个基因之间的基因丢失过程存在差异。脊椎动物HoxC1基因容易丢失基因，其功能域比其他Hox1基因的功能域更具可变性。我们首次描述了四足动物中的HoxC1表达模式。HoxC1在两种蜥蜴的间脑，神经管，背根神经节和肢芽中广泛表达。我们的研究强调了通过密集采样分类学群体来重新研究Hox基因库的价值，以及由于序列资源在评估整个分类群中的基因库方面的增长，其可行性。