Characterization of the complete mitochondrial genome of the Grey-backed Shrike, Lanius tephronotus (Aves: Passeriformes): the first representative of the family Laniidae with a novel CAA stop codon at the end of cox2 gene

Response of an Afro-Palearctic bird migrant to glaciation cycles

We combine tracks of a long-distance migratory bird with high–temporal resolution climate data to reconstruct habitat availability month by month for the past 120,000 y. The seasonal changes of suitable habitat in the past imply that continued seasonal migration was necessary during the glacial maxima. Genomic-based estimates of effective population size indicate that more generally migratory lifestyles can be beneficially adapted to various climatic conditions. Our results provide a major step forward in understanding how migratory species will fare in the future and have important implications for how we understand the role of migration in the distribution of species and potentially speciation.

Migration allows animals to exploit spatially separated and seasonally available resources at a continental to global scale. However, responding to global climatic changes might prove challenging, especially for long-distance intercontinental migrants. During glacial periods, when conditions became too harsh for breeding in the north, avian migrants have been hypothesized to retract their distribution to reside within small refugial areas. Here, we present data showing that an Afro-Palearctic migrant continued seasonal migration, largely within Africa, during previous glacial–interglacial cycles with no obvious impact on population size. Using individual migratory track data to hindcast monthly bioclimatic habitat availability maps through the last 120,000 y, we show altered seasonal use of suitable areas through time. Independently derived effective population sizes indicate a growing population through the last 40,000 y. We conclude that the migratory lifestyle enabled adaptation to shifting climate conditions. This indicates that populations of resource-tracking, long-distance migratory species could expand successfully during warming periods in the past, which could also be the case under future climate scenarios.

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

Passeriformes is the largest group within aves and the phylogenetic relationships between Passeriformes have caused major disagreement in ornithology. Particularly, the phylogenetic relationships between muscicapoidea and sylvioidea are complex, and their taxonomic boundaries have not been clearly defined. Our aim was to study the status of two bird species: Tarsiger cyanurus and Phoenicurus auroreus. Furthermore, we analyzed the phylogenetic relationships of Passeriformes. Complete mitochondrial DNA (mtDNA) sequences of both species were determined and the lengths were 16,803 (T. cyanurus) and 16,772 bp (P. auroreus), respectively. Thirteen protein-coding genes, 22 tRNA genes, two rRNA genes, and one control region were identified in these mtDNAs. The contents of A and T at the base compositions was significantly higher than the content of G and C, and this AT skew was positive, while the GC skew was negative. The monophyly of Passeriformes is divided into four major clades: Corvoidea, Sylvioidea, Passeroidea, and Musicicapoidea. Paridae should be separated from the superfamily Sylvioidea and placed within the superfamily Muscicapoidea. The family Muscicapidae and Corvida were paraphyly, while Carduelis and Emberiza were grouped as a sister taxon. The relationships between some species of the order passeriformes may remain difficult to resolve despite an effort to collect additional characters for phylogenetic analysis. Current research of avian phylogeny should focus on adding characters and taxa and use both effectively to obtain a better resolution for deeper and shallow nodes.

Sequencing and analysis of the complete mitochondrial genome of long-tailed Shrike, Lanius schach (Aves: Laniidae)

The total length of mitochondrial genome of Lanius schach is 16 820 bp and contains 13 protein-coding genes, 22 tRNA genes, 2 rRNA genes and 1 D-loop. The phylogenetic tree of L. schach and 12 other closely species belonging to order Passeriformes was built.

Sequencing and analysis of the complete mitochondrial genome of Rufous-tailed Shrike, Lanius isabellinus (Passeriformes, Laniidae)

The complete mitochondrial genome of the Rufous-tailed Shrike (Lanius isabellinus) was 16 819 bp in length. The GenBank accession number is KP995437 and the contents of A, T, C, and G are 31.1% (5234 bp), 25.5% (4293 bp), 28.7% (4826 bp), and 14.7% (2466 bp), respectively. Gene organization and length are similar to other species of birds. It comprises 13 protein-coding genes, 2 rRNA genes, 22 tRNA genes and a control region. All protein-coding genes use the typical initiation codon ATG, except for COX1 that uses GTG. All the complete stop codons were co-incident with the Black-headed Gull (Chroicocephalus ridibundus) and the Grey-backed Shrike (Lanius tephronotus), except for ND2 that was terminated with TAG. In addition, the phylogenetic relationships of Passeriformes based on complete mitochondrial genome showed that genetic distance of Laniidae and Corvidae was closer than other species.

Sequencing and analysis of the complete mitochondrial genome of Brown Shrike, Lanius cristatus (Passeriformes, Laniidae)

The complete mitochondrial genome of the Brown Shrike (Lanius cristatus) was 16 821 bp in length. The accession number was KT004451 and the contents of A, T, C, and G were 31.10%(5237 bp), 25.60%(4309 bp), 28.60%(4814 bp), and 14.60%(2461 bp), respectively. Gene organization and length was similar to other species of birds. It comprises of 13 protein-coding genes, 2 rRNA genes, 22 tRNA genes and 1 control region. All protein-coding genes use the typical initiation codon ATG, except for COX1 which was initiated with GTG. All the complete stop codon was coincident with the Black-headed Gull (Chroicocephalus ridibundus) and the Grey-backed Shrike (Lanius tephronotus), except for ND2, which was terminated with TAG. In addition, the phylogenetic relationships of Passeriformes based on complete mitochondrial genomes showed that the genetic distance of Laniidae and Corvidae was closer than others.

Complete mitochondrial genome of the Swan Goose (Anser cygnoides L.) and its phylogenetic analysis

In this study, we undertook the first complete the Swan Goose (Anser cygnoides L.) mitochondrial genome. The total length of the mitogenome is 16,739 bp. It contains the typical structure, including 13 protein-coding genes, 22 transfer RNA genes, two ribosomal RNA genes, and one D-loop region. The overall composition of the mitogenome is A (29.2%), G (15.8%), C (32.8%), and T (22.2%). Besides, the base preference of AT was not determined. Twenty-two kinds of tRNA were all typically cloverleaf structures. According to the phylogenetic analysis, A. cygnoides L. has a closer relationship with Anser anser.

Complete mitochondrial genome of the Black-capped Bulbul, Pycnonotus melanicterus (Passeriformes: Pycnonotidae)

The first complete maternally-inherited mitochondrial genome of Pycnonotus melanicterus has been sequenced and annotated in this study. The mitogenome is 17,011 bp in size with an A+T content of 55.15%, consisting of 13 protein-coding genes (PCGs), 22 transfer RNA (tRNA) genes, 2 ribosomal RNA (srRNA and lrRNA) genes, and 2 extensive heteroplasmic control regions. Genome organization and gene arrangements of P. melanicterus are similar to those of other bulbuls. All 13 PCGs initiated with ATG as the start codon, while terminated by seven types of stop codons. All tRNA genes sequences have the potential to fold into typical cloverleaf secondary structures. Gene overlapping was observed in the P. melanicterus mitogenome. Moreover, our results of phylogenetic analysis well support the monophyly of Pycnonotidae as previously studies.