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先有鸡还是先有蛋?
更新时间:2010-04-22      阅读:2459

        鸡在几千年时间里的驯化及其后来向产肉鸡和产蛋鸡的分化,是一个可以提供关于驯化问题及基因型演化问题的很多信息的模型。

        用大型并行测序方法对家鸡及其野生祖先红原鸡所做的一项研究,显示了若干“选择性片段”,在这些片段上,与一种大大增强存活能力的突变相的有利基因变异相对于其他等位基因在频率上有所增加。这些变异中zui引人注目的一个(见于所有家鸡),是位于为刺激甲状腺的荷尔蒙受体编码的一个位点上的变异,它在代谢及脊椎动物生殖时间中起一个关键作用。

        这个片段也许与被驯化动物的一个典型特征相关:没有野生种群中所见的对季节性生殖的严格调控。在肉鸡中所检测到的几个选择性片段上,与生长、食欲和代谢调控相关的基因重叠在一起。

上海劲马生物推荐原文出处:

Nature doi:10.1038/nature08832

Whole-genome resequencing reveals loci under selection during chicken domestication
Carl-Johan Rubin1,10, Michael C. Zody1,2,10, Jonas Eriksson1, Jennifer R. S. Meadows1, Ellen Sherwood3, Matthew T. Webster1, Lin Jiang1, Max Ingman4, Ted Sharpe2, Sojeong Ka5, Finn Hallb??k5, Francois Besnier6, ?rjan Carlborg6, Bertrand Bed’hom7, Michèle Tixier-Boichard7, Per Jensen8, Paul Siegel9, Kerstin Lindblad-Toh1,2 & Leif Andersson1,6

1Department of Medical Biochemistry and Microbiology, Uppsala University, Box 582, SE-75123 Uppsala, Sweden
2Broad Institute of Harvard and MIT, 7 Cambridge Center, Cambridge, Massachusetts 02142, USA
3Department of Cell and Molecular Biology, Karolinska Institutet, SE-17177 Stockholm, Sweden
4Department of Genetics and Pathology, The Rudbeck Laboratory, Uppsala University, SE-75185 Uppsala, Sweden
5Department of Neuroscience, Uppsala University, SE-75124 Uppsala, Sweden
6Department of Animal Breeding and Genetics, Swedish University of Agricultural Sciences, Box 597, SE-75124 Uppsala, Sweden
7INRA, AgroParisTech, UMR1313 Animal Genetics and Integrative Biology, F-78350 Jouy-en-Josas, France
8IFM Biology, Link?ping University, SE-58183 Link?ping, Sweden
9Virginia Polytechnic Institute and State University, Department of Animal and Poultry Sciences, Blacksburg, Virginia 24061-0306, USA

Domestic animals are excellent models for genetic studies of phenotypic evolution1, 2, 3. They have evolved genetic adaptations to a new environment, the farm, and have been subjected to strong human-driven selection leading to remarkable phenotypic changes in morphology, physiology and behaviour. Identifying the genetic changes underlying these developments provides new insight into general mechanisms by which genetic variation shapes phenotypic diversity. Here we describe the use of massively parallel sequencing to identify selective sweeps of favourable alleles and candidate mutations that have had a prominent role in the domestication of chickens (Gallus gallus domesticus) and their subsequent specialization into broiler (meat-producing) and layer (egg-producing) chickens. We have generated 44.5-fold coverage of the chicken genome using pools of genomic DNA representing eight different populations of domestic chickens as well as red jungle fowl (Gallus gallus), the major wild ancestor4. We report more than 7,000,000 single nucleotide polymorphisms, almost 1,300 deletions and a number of putative selective sweeps. One of the most striking selective sweeps found in all domestic chickens occurred at the locus for thyroid stimulating hormone receptor (TSHR), which has a pivotal role in metabolic regulation and photoperiod control of reproduction in vertebrates. Several of the selective sweeps detected in broilers overlapped genes associated with growth, appetite and metabolic regulation. We found little evidence that selection for loss-of-function mutations had a prominent role in chicken domestication, but we detected two deletions in coding sequences that we suggest are functionally important. This study has direct application to animal breeding and enhances the importance of the domestic chicken as a model organism for biomedical research.

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