RESUMEN
The House Crow (Corvus splendens) is a useful study system for investigating the genetic basis of adaptations underpinning successful range expansion. The species originates from the Indian subcontinent, but has successfully spread through a variety of thermal environments across Asia, Africa and Europe. Here, population mitogenomics was used to investigate the colonisation history and to test for signals of molecular selection on the mitochondrial genome. We sequenced the mitogenomes of 89 House Crows spanning four native and five invasive populations. A Bayesian dated phylogeny, based on the 13 mitochondrial protein-coding genes, supports a mid-Pleistocene (~630,000 years ago) divergence between the most distant genetic lineages. Phylogeographic patterns suggest that northern South Asia is the likely centre of origin for the species. Codon-based analyses of selection and assessments of changes in amino acid properties provide evidence of positive selection on the ND2 and ND5 genes against a background of purifying selection across the mitogenome. Protein homology modelling suggests that four amino acid substitutions inferred to be under positive selection may modulate coupling efficiency and proton translocation mediated by OXPHOS complex I. The identified substitutions are found within native House Crow lineages and ecological niche modelling predicts suitable climatic areas for the establishment of crow populations within the invasive range. Mitogenomic patterns in the invasive range of the species are more strongly associated with introduction history than climate. We speculate that invasions of the House Crow have been facilitated by standing genetic variation that accumulated due to diversifying selection within the native range.
Asunto(s)
Evolución Biológica , Cuervos/genética , Genética de Población , Genoma Mitocondrial , Selección Genética , África , Animales , Asia , Teorema de Bayes , Codón , ADN Mitocondrial/genética , Ecosistema , Variación Genética , Filogenia , FilogeografíaRESUMEN
The complete mitochondrial genomes of two jungle crows (Corvus macrorhynchos) were sequenced. DNA was extracted from tissue samples obtained from shed feathers collected in the field in Sri Lanka and sequenced using the Illumina MiSeq Personal Sequencer. Jungle crow mitogenomes have a structural organization typical of the genus Corvus and are 16,927 bp and 17,066 bp in length, both comprising 13 protein-coding genes, 22 transfer RNA genes, 2 ribosomal subunit genes, and a non-coding control region. In addition, we complement already available house crow (Corvus spelendens) mitogenome resources by sequencing an individual from Singapore. A phylogenetic tree constructed from Corvidae family mitogenome sequences available on GenBank is presented. We confirm the monophyly of the genus Corvus and propose to use complete mitogenome resources for further intra- and interspecies genetic studies.
Asunto(s)
Genoma Mitocondrial/genética , Passeriformes/genética , Animales , Plumas/metabolismo , Plumas/fisiología , Passeriformes/clasificación , Filogenia , ARN Ribosómico/genética , ARN de Transferencia/genéticaRESUMEN
The complete mitochondrial genome of the invasive house crow (Corvus splendens) was sequenced (GenBank accession number: KJ766304) using the MiSeq Personal Sequencer (Illumina, San Diego, CA). The mitochondrial genome is 16,962 bp in length, comprising 13 protein-coding genes, 22 transfer RNA genes, 2 ribosomal subunit genes and a non-coding control region. The mitogenome structural organization is identical to that of the other Corvus species and related genera. The overall base composition of C. splendens is 30.65% for A, 29.71% for C, 14.84% for G and 24.80% for T, with an AT content of 55.45%. We propose to use full mitochondrial genome to address taxonomic issues and to study the population genetics of crows.