蒙古羊是尾椎变异比较丰富的地方绵羊品种，前期研究发现蒙古系羊呼伦贝尔羊仅有5~8根尾椎，苏尼特羊尾椎最多达20根，二者杂交可以明显改变尾脂的大小，但不符合孟德尔遗传规律，是受多因素影响的复杂的数量性状，至今未见蒙古羊尾椎变异的分子遗传机理详细报道。因此，本研究以课题组建立的呼伦贝尔短尾羊X苏尼特羊杂交资源群体为试验材料，开展基于家系的极端性状混池重测序，采用集群分离分析的方法定位极端性状受选择的QTL区域，并进行位点的因果突变效应验证，注释受选择的功能基因，检测其在胚胎不同时期的表达水平和分布，研究对尾椎发育和形态建成的重要作用，整合尾椎数表型、基因组重测序和基因表达数据，发现影响尾椎变异的主效基因，构建尾椎变异的分子调控网络，为揭示家畜尾椎遗传变化规律和分子机理提供科学依据。

Mongolian sheep is local sheep breed which has relatively abundant variant of coccygeal vertebra ,in the initial investigation found that Hulunbeier sheep only 5 to 8 coccygeal vertebra, Sunite sheep coccygeal vertebra up to 20, Although the two cross can significantly change the size of the tail fat, not conform to the Mendelian inheritance patterns, it is a complex quantitative trait that is influenced by many factors. The molecular genetic mechanism of Mongolia sheep coccygeal vertebra trait is also not reported.Therefore, in this study, the cross-population between the Hulunbe and Sunite sheep, which were established in the early stage of the research group, were used as the experimental material to carry out the pooling-resequencing analysis of the extreme traits based on the family. The Bulked Segregant analysis method was used to locate funtional QTL for the extreme traits and then Verifing Causal mutation ,annotating the selected functional genes,investigating the expression level and location of the functional genes in the different stages of the embryo to study the important role in the development and form of coccygeal vertebra. Integrating the number of coccygeal vertebrae, Genome resequencing into gene expression data to find major gene that affected variation of coccygeal vertebrae, and to construct the molecular regulation network ，which will provide a scientific basis to clarify livestock coccygeal vertebra genetic variation law and the molecular mechanism.