School of Science, Monash University Malaysia, Jalan Lagoon Selatan, Bandar Sunway, 47500, Petaling Jaya, Selangor, Malaysia.
Monash University Malaysia Genomics Facility, Monash University Malaysia, Jalan Lagoon Selatan, Bandar Sunway, 47500, Petaling Jaya, Selangor, Malaysia.
Heredity (Edinb). 2018 Apr;120(4):296-309. doi: 10.1038/s41437-017-0020-7. Epub 2017 Nov 28.
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.
家鸦(Corvus splendens)是一个有用的研究系统,可用于研究成功扩展范围所必需的适应遗传基础。该物种起源于印度次大陆,但已成功通过亚洲、非洲和欧洲的各种热环境传播。在这里,通过群体线粒体基因组学研究了其殖民历史,并检验了线粒体基因组上分子选择的信号。我们对 89 只家鸦的线粒体基因组进行了测序,这些样本来自四个原生种群和五个入侵种群。基于 13 个线粒体蛋白编码基因的贝叶斯日期系统发育树支持了最远距离遗传谱系在中更新世(约 63 万年前)的分歧。系统地理学模式表明,南亚北部可能是该物种的起源中心。基于密码子的选择分析和氨基酸性质变化的评估提供了证据,表明 ND2 和 ND5 基因在整个线粒体基因组中受到纯化选择的背景下受到正选择的影响。蛋白质同源建模表明,推断出的四个受正选择影响的氨基酸取代可能调节氧化磷酸化复合物 I 介导的偶联效率和质子易位。这些推断的取代发生在原生家鸦谱系中,生态位模型预测了在入侵范围内建立乌鸦种群的适宜气候区域。该物种入侵范围内的线粒体基因组模式与引入历史的相关性强于气候。我们推测,家鸦的入侵是由于在原生范围内的多样化选择积累了遗传变异而得以实现的。