Selected Lark Mitochondrial Genomes Provide Insights into the Evolution of Second Control Region with Tandem Repeats in Alaudidae (Aves, Passeriformes)

The control region ( ) regulates the replication and transcription of the mitochondrial genome (mitogenome). Some avian mitogenomes possess two , and the second control region ( ) may enhance replication and transcription; however, the in lark mitogenome appears to be undergoing loss and is accompanied by tandem repeats. Here, we characterized six lark mitogenomes from , , , and and reconstructed the phylogeny of Passerida. Through further comparative analysis among larks, we traced the evolutionary process of . The mitochondrial gene orders were conserved in all published lark mitogenomes, with with tandem repeat- . Phylogenetic analysis revealed Alaudidae and Panuridae are sister groups at the base of Sylvioidea, and sporadic losses of may occur in their common ancestor. sequence and phylogeny analysis indicated tandem repeats were generated within , originating in the ancestor of all larks, rather than inherited from . The secondary structure comparison of tandem repeat units within and between species suggested slipped-strand mispairing and DNA turnover as suitable models for explaining the origin and evolution of these repeats. This study reveals the evolutionary process of the containing tandem repeat in Alaudidae, providing reference for understanding the evolutionary characteristics and dynamics of tandem repeats.