据PhysOrg网站2006年8月16日报道,本周,包括澳大利亚联邦科学与工业研究组织(CSIRO)和新西兰农业研究协会在内的国际研究组织的科学家完成了牛基因组测序的大部分工作,这项成果使科学家改善牛类健康和疾病控制、提高牛肉和奶制品营养价值的能力大幅提升。
据介绍,新的全基因组序列包含了29亿个碱基对,这比以前版本的牛基因序列多了三分之一以上。除测序工作以外,科学家对这些碱基对的差异性,即单核苷酸多态性(SNPs)也进行研究。碱基对的差异可以影响一个基因的功能,决定牲畜产量的高低。作为一种基因标记,对2百多万种的单核苷酸多态性进行研究也是此项基因测序工作的一部分。
该项研究得到美国5300万美元的资助,澳大利亚联邦科学与工业研究组织博士罗斯•特拉姆是“牛基因组序列项目”的澳大利亚代表。他说,“我们可以用这些数据来对那些与牛哺乳、繁殖、肌肉生长、生长率和疾病抵御等重要功能相关的基因进行鉴别。新的牛基因图标志着基因测序阶段的工作已经接近尾声,现在主要任务就是对有用数据进行分析。这是一个非常重要的消息。在今后50年的时间里,我们将在牛畜饲养和生产方面取得长足进步,我们将结束持续了8000年的传统畜牧模式”。
牛遗传学家们将用牛基因组作为一个模板进行同类牛群和不同类牛群之间,以及牛与其它类型哺乳动物之间遗传变异的研究。
澳大利亚联邦科学与工业研究组织家畜业生物信息研究带头人布赖恩•达尔利姆普勒认为,新的牛基因数据非常有价值,因为它能为研究人员提供一个更加完善的牛基因图谱,帮助研究人员修改脱氧核糖核酸代码以获得想要的产品特性。达尔利姆普勒说,“我们可以使用这些数据来对那些与牛哺乳、繁殖、肌肉生长、生长率和抗病性等重要功能相关的基因进行鉴别”。
赫里福种食用牛(Hereford breed)被选定为此项基因排序工程的样品牛,此项工程起始于2003年12月份。科学家还对荷尔斯坦牛、安格斯牛、泽西种乳牛、利姆辛牛、挪威红牛和婆罗门牛的基因进行了排序,以鉴定这些不同种类牛之间的特殊遗传差异性。
达尔利姆普勒博士说,“这只是我们制造动物和食物革命的开端。一旦我们拥有一套完整的基因,比如能影响肉嫩度的基因,我们将来就能对一种特定类型的动物喂养特定类型的草料或者谷物,使它们能始终长出特定标准的嫩肉和像大理石花纹一样肥瘦相间的肉”。他说,尽管几个世纪以来一直进行的同系繁殖创造出了不同的品种,但是这种繁殖保持了“巨大”的遗传差异性。
基因组数据可以通过许多公共数据库获得,包括贝乐医学院人类基因组测序中心数据库 (http://www.hgsc.bcm.tmc.edu,);美国国家卫生研究院生物技术信息中心的GenBank数据库 (http://www.ncbi.nih.gov/Genbank,);欧洲分子生物学实验室测序数据库 EMBL Bank (http://www.ebi.ac.uk/embl/index.html,);日本DNA数据库 (http://www.ddbj.nig.ac.jp,)。
部分英文原文:
Completed genome set to transform the cow
Developed by an international consortium of research organisations, including CSIRO and AgResearch New Zealand, the new bovine sequence contains 2.9 billion DNA base pairs and incorporates one-third more data than earlier versions.
Differences in just one of these base pairs (known as single nucleotide polymorphisms or SNPs) can affect the functioning of a gene and mean the difference between a highly productive and a poorly performing animal. Over two million of these SNPs, which are genetic signposts or markers, were identified as part of the project.
“We can use this data to identify those genes that are involved in important functions like lactation, reproduction, muscling, growth rate and disease resistance”Australia’s representative on the US $53 million Bovine Genome Sequencing Project, CSIRO’s Dr Ross Tellam, says the new map marks the end of the sequencing phase of the project, with the focus now on analysing the available data.
“This is very valuable information,” Dr Tellam says. “We could potentially achieve as much improvement in cattle breeding and production in 50 years as we have over the last 8000 years of traditional farming.”
Cattle geneticists will use the bovine genome as a template to highlight genetic variation within and between cattle breeds, and between cattle and other mammal species.
The head of bioinformatics research at CSIRO Livestock Industries, Dr Brian Dalrymple, says the new data is very valuable because it provides researchers with a more complete picture of the genes in a cow and how variations in the DNA code influence desirable production traits.
“We can use this data to identify those genes that are involved in important functions like lactation, reproduction, muscling, growth rate and disease resistance,” Dr Dalrymple says.
The Hereford breed was selected for the bulk of the sequencing project, which began in December 2003. Holstein, Angus, Jersey, Limousin, Norwegian Red and Brahman animals were also sequenced to detect specific genetic differences between breeds.