Science2014-06-23 3:47 PM

 描述2种乌鸦基因组 The genomic landscape underlying phenotypic integrity in the face of gene flow in crows

论文摘要 

尽管在欧洲的2个不同区域中它们的基因进行着频繁的交换,全黑食腐乌鸦与灰色带顶饰羽乌鸦仍然维持着非常不同的羽毛;这两种乌鸦的活动范围有所重叠。如今,一项新的研究提示,让这2个物种保持分开的基因差异局限于这两种鸟的不到1%的基因组内。食腐乌鸦及顶饰羽乌鸦常被视作代表着食腐乌鸦的2个亚种,尽管某些科学家声称它们是完全不同的物种。Jelmer Poelstra及其同事将来自欧洲的混杂(或范围重叠)区域的60个乌鸦的基因组——它们中某些为小嘴乌鸦而另外的为冠小嘴乌鸦——进行了比较并发现,只要有若干基因(不到整个基因组的0.28%)的表达差异就足以保持乌鸦物种外观上的不同。据研究人员披露,这一特别的1.95兆碱基对长的基因组块位于该禽类的第18条染色体上,该染色体含有与色素颜色、视觉感知及荷尔蒙平衡有关的基因。他们说,那些基因,连同某些其它位于类似但甚至更小的所谓“物种形成岛”上的基因在顶羽饰乌鸦中一直表达不足。该发现提示,这些乌鸦的不同基因表达模式足以驱动它们之间的物种形成,即使当物种间会发生交配时。由Peter de Knijff撰写的一篇《观点栏目》文章对该发现及其对物种形成的意义进行了更为详细的解释。

Abstract 

The importance, extent, and mode of interspecific gene flow for the evolution of species has long been debated. Characterization of genomic differentiation in a classic example of hybridization between all-black carrion crows and gray-coated hooded crows identified genome-wide introgression extending far beyond the morphological hybrid zone. Gene expression divergence was concentrated in pigmentation genes expressed in gray versus black feather follicles. Only a small number of narrow genomic islands exhibited resistance to gene flow. One prominent genomic region (<2 megabases) harbored 81 of all 82 fixed differences (of 8.4 million single-nucleotide polymorphisms in total) linking genes involved in pigmentation and in visual perception—a genomic signal reflecting color-mediated prezygotic isolation. Thus, localized genomic selection can cause marked heterogeneity in introgression landscapes while maintaining phenotypic divergence.

Editor's Summary

Crows of a feather flock together

Closely related species with overlapping ranges typically evolve genetic barriers to prevent crossbreeding. Poelstra et al. sequenced genes from two species of central European crows: gray-bodied hooded crows and black carrion crows (see the Perspective by de Knijff). Although most of the genomes shared genes between the two species, one region that affected coat color and color vision differed. The authors suggest that black and gray-coated crows prefer to mate with birds like themselves.

KEYWORDS

SHARE & LIKE

COMMENTS

ABOUT THE AUTHOR

Science

Science Magazine

0 Following 18 Fans 0 Projects 236 Articles

SIMILAR ARTICLES

AbstractThe conservation of sleep across all animal species suggests that sleep serves a vital function. We here report that sleep has a critical funct

Read More

Introduction Recent decades have seen a major international effort to inventory tree communities in the Amazon Basin and Guiana Shield (Amazonia), but

Read More

IntroductionInitiation of protein synthesis is a key step in the control of gene expression. In eukaryotes, initiation is a highly complex process that

Read More

Abstract For decades, social psychological theories have posited that the automatic processes captured by implicit measures have implications for soci

Read More

论文摘要动物界最复杂的眼睛可以在物种口足类甲壳动物(濑尿虾)中找到,其中一些有12种不同类型的光感受器,每种各取样较窄的一组波长,范围包含了深紫外光到远红光(300到720纳米)。在功能上,这种彩色复杂性被视作是谜。当3种或4种色彩通道对色彩辨认来说已经足够时,为何要使用12种色彩通道?对口足类动物行

Read More

论文摘要 首先,在一篇“评论”文章中,Thomas Piketty 和 Emmanuel Saez用“世界顶级收入数据库(WTID)”来比较这两个数值多年来是如何在欧洲和美国演变的;WTID包括了一个世纪之久的有关全球收入的数据以及2个世纪之久的有关个人财富的数据。据研究人员披露,在20世纪之交的时候

Read More

IntroductionCensorship has a long history in China, extending from the efforts of Emperor Qin to burn Confucian texts in the third century BCE to the c

Read More

Many animals, on air, water, or land, navigate in three-dimensional (3D) environments, yet it remains unclear how brain circuits encode the animal's 3D

Read More

Many animals, on air, water, or land, navigate in three-dimensional (3D) environments, yet it remains unclear how brain circuits encode the animal's 3D

Read More

Like mammalian neurons, Caenorhabditis elegans neurons lose axon regeneration ability as they age, but it is not known why. Here, we report that let-7

Read More