据4月24日的《科学》杂志报道说,研究人员现在已经完成了对整个牛染色体组的测序,这一成就对我们加深了解哺乳动物的进化、加速牛奶和肉制品的基因改良并由此而更好地了解人类疾病以及对它们的相关治疗都会有促进作用。
在2篇独立的报告中,Richard Gibbs及其同僚重点介绍了Bovine Genome Sequencing and Analysis Consortium的最近的发现,该项目对牛的基因组进行了分辨率精细的测序;而Bovine HapMap Consortium则将研究焦点放在对牲畜进化和驯养历史的追踪工作上。 对这2个项目进行研究的工作人员发现,牛的基因组含有至少2万2000个基因,其中大约有1万4345个基因在7种其它的哺乳动物种系中具有对应的基因。
这些发现显示,在牛的进化和驯养过程中,基因的数量和构成的变化是如何改变牛的生物学系统并对它们的繁殖、免疫能力、乳汁分泌和消化造成了最为显著的影响的。 这些研究人员还对来自19个不同地理和在生物学上混杂繁殖的497头不同牛只DNA中的3万7470种差异进行了调查。他们发现,母牛的进化与我们人类本身的进化截然不同,它们从一个有着非常大的有效祖先群体到近期发生的快速的群体下降,而不是反过来的那种一种情形。 文章的作者将这种进化归因于与以往驯化活动、因农业专门化所作的选择以及与动物豢养的形成相关的遗传学瓶颈。 但是,牛品种中的多样性的现有水平看来至少与那些在人类群体中的水平一样地强健有力。
在一篇Perspective中,Harris Lewin对这些发现进行了更为详细的探讨,并重点介绍了其对人类健康和可持续性农业的意义。(生物谷Bioon.com)
生物谷推荐原始出处:
Science 24 April 2009:DOI: 10.1126/science.1169588
The Genome Sequence of Taurine Cattle: A Window to Ruminant Biology and Evolution
The Bovine Genome Sequencing and Analysis Consortium,* Christine G. Elsik,1 Ross L. Tellam,2 Kim C. Worley3
To understand the biology and evolution of ruminants, the cattle genome was sequenced to about sevenfold coverage. The cattle genome contains a minimum of 22,000 genes, with a core set of 14,345 orthologs shared among seven mammalian species of which 1217 are absent or undetected in noneutherian (marsupial or monotreme) genomes. Cattle-specific evolutionary breakpoint regions in chromosomes have a higher density of segmental duplications, enrichment of repetitive elements, and species-specific variations in genes associated with lactation and immune responsiveness. Genes involved in metabolism are generally highly conserved, although five metabolic genes are deleted or extensively diverged from their human orthologs. The cattle genome sequence thus provides a resource for understanding mammalian evolution and accelerating livestock genetic improvement for milk and meat production.
1 Department of Biology, 406 Reiss, Georgetown University, 37th and O Streets, NW, Washington, DC 20057, USA.
2 CSIRO Livestock Industries, 306 Carmody Road, St. Lucia, QLD 4067, Australia.
3 Human Genome Sequencing Center, Department of Molecular and Human Genetics, Baylor College of Medicine, MS BCM226, One Baylor Plaza, Houston, TX 77030, USA.