nature20121129-5

来自瑞典乌普萨拉大学的科学家通过比较姬鹟每个物种10个样本的基因组图谱,确定了50个区域显示尤其高水平分离。这些“分离岛”与有丝分裂过程中染色体分离相关的着丝粒和其他重复序列区域相一致。这些研究发现提出了一种可能性即这些重要的染色体重复元件帮助推动了物种形成。

-2012年11月29日《自然》

中文翻译


【题目】姬鹟中物种分化的基因组图谱

【译文】阐明谱系间差异的基因组图谱是理解物种形成的关键。自然杂交的白领姬鹟和斑姬鹟是重要的鸟类物种形成模式,它们可以表现出合子前隔离和合子后隔离。我们测序并组装了1.1Gb大小的姬鹟基因组,利用一种低密度连锁图将集合定位于染色体,并对每一物种的群体样本进行重测序。本研究表明物种分化的基因组景观是高度异质性的,具有约50个分离岛,比基因组背景具有50倍以上的序列差异性。这些非随机分布的分离岛,在每个染色体(不考虑染色体大小)中具有1-3个明显的分化区域,这些分离岛的特征是核苷酸多样性的降低,等位基因频率分布偏曲,连锁不平衡水平升高以及共有多态性比例的降低,这暗示自然选择的平行事件。基因组区差异峰的相似性对序列组装有抗性,包括着丝粒和端粒,表明复杂重复结构可能驱动物种分化。Z染色体物种分化的更高背景水平以及共享多态性的较低比例表明性染色体和常染色体在物种形成的不同阶段。本研究为物种形成基因组的出现提供了一种路标。

英文原稿


[Title]: The genomic landscape of species divergence in Ficedula flycatchers

[Authors]:Hans Ellegren,1 Linnéa Smeds,1 Reto Burri,1 Pall I. Olason,1 Niclas Backström,1 Takeshi Kawakami,1 Axel Künstner,1, 3 Hannu Mäkinen,1 Krystyna Nadachowska-Brzyska,1 Anna Qvarnström,2 Severin Uebbing1 & Jochen B. W. Wolf1

[Abstract]Unravelling the genomic landscape of divergence between lineages is key to understanding speciation. The naturally hybridizing collared flycatcher and pied flycatcher are important avian speciation models that show pre- as well as postzygotic isolation. We sequenced and assembled the 1.1-Gb flycatcher genome, physically mapped the assembly to chromosomes using a low-density linkage map and re-sequenced population samples of each species. Here we show that the genomic landscape of species differentiation is highly heterogeneous with approximately 50 ‘divergence islands’ showing up to 50-fold higher sequence divergence than the genomic background. These non-randomly distributed islands, with between one and three regions of elevated divergence per chromosome irrespective of chromosome size, are characterized by reduced levels of nucleotide diversity, skewed allele-frequency spectra, elevated levels of linkage disequilibrium and reduced proportions of shared polymorphisms in both species, indicative of parallel episodes of selection. Proximity of divergence peaks to genomic regions resistant to sequence assembly, potentially including centromeres and telomeres, indicate that complex repeat structures may drive species divergence. A much higher background level of species divergence of the Z chromosome, and a lower proportion of shared polymorphisms, indicate that sex chromosomes and autosomes are at different stages of speciation. This study provides a roadmap to the emerging field of speciation genomics.

原文地址

http://www.nature.com/nature/journal/v491/n7426/full/nature11584.html

本站声明: 生物文库所有文章欢迎转载,所有文章未说明,均属于原创,转载均请注明出处。
本文链接: http://www.bioku.cn/201301/nature-genomic-landscape-species-divergence-flycatcher/
版权所有: 生物文库 - 生物医学、生物技术核心期刊文摘

留言


9 − = 四


沪ICP备12028140号
点击这里给我发消息   点击这里给我发消息