The rearrangement of 37 genes with one control region, firstly identified in Gallus gallus mitogenome, is believed to be ancestral for all Aves. However, mitogenomic sequences obtained in recent years revealed that many avian mitogenomes contain duplicated regions that were omitted in previous genomic versions. Their evolution and mechanism of duplication are still poorly understood. The order of Accipitriformes is especially interesting in this context because its representatives contain a duplicated control region in various stages of degeneration. Therefore, we applied an appropriate PCR strategy to look for duplications within the mitogenomes of the early diverged species Sagittarius serpentarius and Cathartiformes, which is a sister order to Accipitriformes. The analyses revealed the same duplicated gene order in all examined taxa and the common ancestor of these groups. The duplicated regions were subjected to gradual degeneration and homogenization during concerted evolution. The latter process occurred recently in the species of Cathartiformes as well as in the early diverged lineages of Accipitriformes, that is, Sagittarius serpentarius and Pandion haliaetus. However, in other lineages, that is, Pernis ptilorhynchus, as well as representatives of Aegypiinae, Aquilinae, and five related subfamilies of Accipitriformes (Accipitrinae, Circinae, Buteoninae, Haliaeetinae, and Milvinae), the duplications were evolving independently for at least 14–47 Myr. Different portions of control regions in Cathartiformes showed conflicting phylogenetic signals indicating that some sections of these regions were homogenized at a frequency higher than the rate of speciation, whereas others have still evolved separately.

中文翻译：

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鹰形目和猫形目的线粒体基因组经历了祖先和最近的复制，随后逐渐退化


37 个基因与一个控制区域的重排首次在原鸡有丝分裂基因组中被发现，被认为是所有鸟类的祖先。然而，近年来获得的线粒体基因组序列表明，许多鸟类线粒体基因组包含以前基因组版本中省略的重复区域。它们的进化和复制机制仍然知之甚少。鹰形目在这种情况下特别有趣，因为它的代表在不同的退化阶段包含重复的控制区域。因此，我们应用适当的 PCR 策略来寻找早期分化物种 Sagittarius serpentarius 和 Cathartiformes（Accipitriformes 的姐妹目）的有丝分裂基因组内的重复。分析揭示了所有检查的分类群中相同的重复基因顺序以及这些群体的共同祖先。重复的区域在协同进化过程中逐渐退化和同质化。后一个过程最近发生在 Cathartiformes 物种以及 Accipitriformes 的早期分歧谱系中，即 Sagittarius serpentarius 和 Pandion haliaetus 中。然而，在其他谱系中，即Pernis ptilorhynchus，以及Aegypiinae、Aquilinae和Accipitriformes的五个相关亚科（Accipitrinae、Circinae、Buteoninae、Haliaeetinae和Milvinae）的代表，重复至少独立进化了14- 47 密尔。 Cathartiformes 控制区域的不同部分显示出相互矛盾的系统发育信号，表明这些区域的某些部分以高于物种形成速率的频率同质化，而其他部分仍然单独进化。