The complete mitochondrial genomes of Tarsiger cyanurus and Phoenicurus auroreus: a phylogenetic analysis of Passeriformes

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

The control region (CR) regulates the replication and transcription of the mitochondrial genome (mitogenome). Some avian mitogenomes possess two CRs, and the second control region (CR2) may enhance replication and transcription; however, the CR2 in lark mitogenome appears to be undergoing loss and is accompanied by tandem repeats. Here, we characterized six lark mitogenomes from Alaudala cheleensis, Eremophila alpestris, Alauda razae, and Calandrella cinerea and reconstructed the phylogeny of Passerida. Through further comparative analysis among larks, we traced the evolutionary process of CR2. The mitochondrial gene orders were conserved in all published lark mitogenomes, with Cytb-trnT-CR1-trnP-ND6-trnE-remnant CR2 with tandem repeat-trnF-rrnS. Phylogenetic analysis revealed Alaudidae and Panuridae are sister groups at the base of Sylvioidea, and sporadic losses of CR2 may occur in their common ancestor. CR sequence and phylogeny analysis indicated CR2 tandem repeats were generated within CR2, originating in the ancestor of all larks, rather than inherited from CR1. 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 CR2 containing tandem repeat in Alaudidae, providing reference for understanding the evolutionary characteristics and dynamics of tandem repeats.

The published complete mitochondrial genome of Blue-fronted Redstart (Phoenicurus frontalis) is a chimera and includes DNA from Pink-rumped Rosefinch Carpodacus waltoni eos (Aves: Passeriformes)

The complete mitochondrial genome of Blue-fronted Redstart (Phoenicurus frontalis), GenBank accession number MT360379 (NC_053917), was published by Li and colleages in 2020. Here we show that this mitogenome is actually a chimera containing DNA fragments of both P. frontalis (15,518 bp, 92.5%) and Pink-rumped Rosefinch (Carpodacus waltoni eos, 1258 bp, 7.5%). This mitogenome has been re-used in at least three phylogenies. Our study confirms that mitogenomes are best verified with multiple gene trees, and that any anomalies should be investigated by direct comparison of sequences.

Complete Mitochondrial Genome and Phylogenetic Analysis of Tarsiger indicus (Aves: Passeriformes: Muscicapidae)

Tarsiger indicus (Vieillot, 1817), the White-browed Bush Robin, is a small passerine bird widely distributed in Asian countries. Here, we successfully sequenced its mitogenome using the Illumina Novaseq 6000 platform (Illumina, San Diego, CA, USA) for PE 2 × 150 bp sequencing. Combined with other published mitogenomes, we conducted the first comprehensive comparative mitogenome analysis of Muscicapidae birds and reconstructed the phylogenetic relationships between Muscicapidae and related groups. The T. indicus mitogenome was 16,723 bp in size, and it possessed the typical avian mitogenome structure and organization. Most PCGs of T. indicus were initiated strictly with the typical start codon ATG, while COX1 and ND2 were started with GTG. RSCU statistics showed that CUA, CGA, and GCC were relatively high frequency in the T. indicus mitogenome. T. cyanurus and T. indicus shared very similar mitogenomic features. All 13 PCGs of Muscicapidae mitogenomes had experienced purifying selection. Specifically, ATP8 had the highest rate of evolution (0.13296), whereas COX1 had the lowest (0.01373). The monophylies of Muscicapidae, Turdidae, and Paradoxornithidae were strongly supported. The clade of ((Muscicapidae + Turdidae) + Sturnidae) in Passeriformes was supported by both Bayesian Inference and Maximum likelihood analyses. The latest taxonomic status of many passerine birds with complex taxonomic histories were also supported. For example, Monticola gularis, T. indicus, and T. cyanurus were allocated to Turdidae in other literature; our phylogenetic topologies clearly supported their membership in Muscicapidae; Paradoxornis heudei, Suthora webbiana, S. nipalensis, and S. fulvifrons were formerly classified into Muscicapidae; we supported their membership in Paradoxornithidae; Culicicapa ceylonensis was originally classified as a member of Muscicapidae; our results are consistent with a position in Stenostiridae. Our study enriches the genetic data of T. indicus and provides new insights into the molecular phylogeny and evolution of passerine birds.

Identification and phylogenetic analysis in Pterorhinuschinensis (Aves, Passeriformes, Leiothrichidae) based on complete mitogenome

The Black-throated Laughingthrush (Pterorhinuschinensis) is a bird belonging to the order Passeriformes and the family Leiothrichidae, and is found in Cambodia, China, Laos, Myanmar, Thailand and Vietnam. Pterorhinuschinensis was once classified as belonging to the genus Garrulax. However, recent research has reclassified it in the genus Pterorhinus. In this study, we sequenced and characterized the complete mitogenome of P.chinensis. The complete mitochondrial genome of P.chinensis is 17,827 bp in length. It consists of 13 PCGs, 22 tRNAs, two rRNAs, and two control regions. All genes are coded on the H-strand, except for one PCG (nad6) and eight tRNAs. All PCGs are initiated with ATG and stopped by five types of stop codons. Our comparative analyses show irregular gene rearrangement between trnT and trnP genes with another similar control region emerging between trnE and trnF genes compared with the ancestral mitochondrial gene order, called "duplicate CR gene order". The phylogenetic position of P.chinensis and phylogenetic relationships among members of Leiothrichidae are assessed based on complete mitogenomes. Phylogenetic relationships based on Bayesian inference and maximum likelihood methods showed that Garrulax and (Pterorhinus + Ianthocincla) formed a clade. Leiothrix and Liocichla also formed a clade. Our study provides support for the transfer of P.chinensis from Garrulax to Pterorhinus. Our results provide mitochondrial genome data to further understand the mitochondrial genome characteristics and taxonomic status of Leiothrichidae.