Differential divergence in autosomes and sex chromosomes is associated with intra-island diversification at a very small spatial scale in a songbird lineage
Differential divergence in autosomes and sex chromosomes is associated with intra-island diversification at a very small spatial scale in a songbird lineage
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DOI：
10.1111/mec.15396
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发表时间：
2020-03-01
影响因子：
4.9
通讯作者：
Mil, Borja
中科院分区：
文献类型：
--
作者：
Bourgeois, Yann X. C.;Bertrand, Joris A. M.;Mil, Borja
最近分歧类群表现出显着的表型和生态多样性提供了最佳的系统，以了解物种形成的遗传过程。我们使用全基因组标记，以调查的多样化的留尼汪岛灰绣眼（Zosterops borbonicus）的小火山岛留尼汪岛（马斯克林群岛），在那里这个物种复杂的表现出四个地理形式，parapatrically分布在整个岛屿和不同的羽毛颜色显着。一种仅限于高地的形式被陡峭的生态梯度与三种不同的低地形式分开，这些形式在与环境变量无关的狭窄混合区相遇。基于测序基因分型和合并RAD-seq方法的单核苷酸多态性数据的基因组变异分析表明，与海拔相关的选择特征可以在基因组的多个区域发现，而与低地形式相关的大多数基因座位于Z性染色体上。我们确定TYRP 1，一个Z-连锁的颜色基因，作为一个可能的候选位点之间的低地形式的颜色变化。人口统计模型的测试表明，高地和低地的形式在基因流的存在下发生了分歧，而分歧的进展是由于基因流受到基因组中基因座选择的限制。该系统有望研究适应和生殖隔离如何在物种形成过程的多个阶段形成基因组景观的分歧。
Recently diverged taxa showing marked phenotypic and ecological diversity provide optimal systems to understand the genetic processes underlying speciation. We used genome-wide markers to investigate the diversification of the Reunion grey white-eye (Zosterops borbonicus) on the small volcanic island of Reunion (Mascarene archipelago), where this species complex exhibits four geographical forms that are parapatrically distributed across the island and differ strikingly in plumage colour. One form restricted to the highlands is separated by a steep ecological gradient from three distinct lowland forms which meet at narrow hybrid zones that are not associated with environmental variables. Analyses of genomic variation based on single nucleotide polymorphism data from genotyping-by-sequencing and pooled RAD-seq approaches show that signatures of selection associated with elevation can be found at multiple regions across the genome, whereas most loci associated with the lowland forms are located on the Z sex chromosome. We identified TYRP1, a Z-linked colour gene, as a likely candidate locus underlying colour variation among lowland forms. Tests of demographic models revealed that highland and lowland forms diverged in the presence of gene flow, and divergence has progressed as gene flow was restricted by selection at loci across the genome. This system holds promise for investigating how adaptation and reproductive isolation shape the genomic landscape of divergence at multiple stages of the speciation process.