基于群体基因组学的绒山羊绒性状相关基因及基因互作鉴定

Despite abundant excellent cashmere goat breeds and the world's largest producer of cashmere in China, little is known about the molecular mechanisms of cashmere formation and development. The special cashmere traits in cashmere goats are shaped by selection resulting from both domestication and natural selection. The genetic basis underlying cashmere traits is very complex, involving multiple genes affecting cashmere traits in an independent or interactive manner. In present project, we will employ a population-genomics approach to identify highly differentiated genomic regions between cashmere (Tibetan cashmere goat, Inner Mongolia cashmere goat and Liaoning cashmere goat) and non-cashmere goats (Beichuan White goat,Zhongwei goat and Boer goat) using the Illumina 50K SNP array as well as gene-gene interactions using a haplotype-based full-model logistic regression based on case-control design, with a major focus on detecting promising genes, genomic regions and gene-gene interactions associated with cashmere traits in certain breed and multiple breeds. It is expected that the completion of the project will not only help to systemically understand the genetic basis of cashmere traits, but also promote the utility of animal genetic resources and the development of cashmere goat breeding in China.

我国拥有优异的绒山羊品种资源以及世界上最大的羊绒生产量，然而绒生产性状的分子基础仍不明确。绒山羊优异的绒性状是长期人工及自然选择作用下形成的，其遗传学机理非常复杂，多个基因通过单独或与其他基因的交互作用同时对其产生影响。本项目采用山羊全基因组SNP芯片对我国代表性的3个绒山羊品种（西藏绒山羊、内蒙古绒山羊和辽宁绒山羊）和3个非绒山羊品种（北川白山羊，波尔山羊和中卫山羊）各50只进行分型，基于群体基因组学原理对绒山羊和非绒山羊高度分化的基因组区域进行扫描，同时运用case-control设计的单体型logistic回归模型对绒山羊基因组中LD block之间的基因互作模式进行探索，从而挖掘绒山羊品种特异性及品种间共有的与绒性状相关的基因、基因组区域以及基因互作对。该研究能够帮助我们系统的认识绒生产性状的分子机理，同时对我国优异种质资源的利用及我国绒山羊育种有十分重要的意义。

绒山羊，是我国畜牧业的重要组成部分，是主导国际羊绒市场的畜品种之一。中国是全球羊绒生产和出口第一大国，羊绒产业的发展繁荣具有战略意义。我国当前高端羊绒刚性需求与羊绒提质增效缓慢、环境荒漠化加剧的矛盾日益凸显，解析羊绒生长机制并利用分子标记进行绒性状的改良是绒羊产业未来可持续发展的战略需求。本项目采用山羊基因组SNP芯片对我国多个代表性的绒山羊品种（西藏绒山羊、内蒙古绒山羊、辽宁绒山羊、柴达木绒山羊等）和国内外非绒山羊品种高度分化的基因组区域进行扫描，筛选出FGF5等10余个候选基因；并构建自然光照和短日照条件下的不同毛囊发育周期的绒山羊皮肤转录组数据库，利用基因与lincRNA共表达互作网络的分析，筛选出19个互作对，其中一个互作对包括毛囊关键转录因子DLX3/DLX4基因座位；筛选出8个山羊次级毛囊特异性表达的转录因子，对其中的未知转录因子CSDC2进行了细胞功能实验，发现其具有促进细胞增殖，调控毛囊发育通路的重要作用，推测该基因可能是毛囊生长的新基因。本项目从基因组、转录组、组织和细胞学等多维度，对绒性状的功能基因进行了深度发掘，发现的重要功能基因为绒山羊的分子育种提供重要素材。