亚丁牦牛和拉日马牦牛遗传多样性及遗传结构分析

亚丁牦牛和拉日马牦牛均为肉乳兼用型优良地方牦牛资源，本研究旨在探究亚丁牦牛和拉日马牦牛的遗传多样性及各牦牛群体间的亲缘关系，对亚丁牦牛、拉日马牦牛以及其他7个地方牦牛群体（九龙牦牛、麦洼牦牛、金川牦牛、昌台牦牛、中甸牦牛、玉树牦牛、类乌齐牦牛）进行RAD简化基因组测序，基于检测到的SNP信息计算遗传统计量。结果表明，亚丁牦牛和拉日马牦牛的观测杂合度分别为0.2186、0.2233，亚丁牦牛遗传多样性较贫乏。亚丁牦牛的平均遗传分化指数Fst值最高为0.0653，与其他8个牦牛群体存在中度分化，Structure分析显示其血统构成纯正，可列为一个独立遗传资源。拉日马牦牛Fst值最低为0.0443，其群体遗传结构较复杂，与九龙牦牛和麦洼牦牛存在基因交流，属麦洼牦牛的祖先群之一。亚丁牦牛和拉日马牦牛均值得进一步研究和保护，研究结果对牦牛遗传资源的保护与利用具有重要意义。

Genetic structure and diversity of Yading yak and Larima yak populations

Yading yak and Larima yak are excellent local yak resources for meat and milk production. The aims of this study were to explore the genetic diversity of Yading yak and Larima yak and the genetic relationships among yak populations. We conducted restriction site associated DNA simplified genome sequencing for Yading yak， Larima yak， and seven other local yak populations （Jiulong yak， Maiwa yak， Jinchuan yak， Changtai yak， Zhongdian yak， Yushu yak， and Leiwuqi yak）. Genetic statistics were calculated based on the detected single nucleotide polymorphism information. The observed heterozygosity values of Yading yak and Larima yak populations were 0.2186 and 0.2233， respectively. The genetic diversity of Yading yak was relatively poor. The average genetic differentiation index （Fst value） of Yading yak was 0.0653， which was moderately different from those of other Yak populations. A Structure analysis showed that the pedigree of Yading yak is pure， so it can be classified as an independent genetic resource. The lowest Fst value was that of Larima yak （0.0443）. Our analyses suggest that the population genetic structure is more complicated for Larima yak than for other yak populations. Our results indicate that here have been genetic exchanges between Larima yak and Jiulong yak as well as Maiwa yak， and that Larima yak is one of the ancestor groups of Maiwa yak. Further research on Yading yak and Larima yak is warranted， and both populations require protection. The results of this study will be useful for developing strategies to protect and utilize yak genetic resources.