Key Laboratory of Animal Genetics and Breeding on Tibetan Plateau, Ministry of Agriculture and Rural Affairs, Lanzhou Institute of Husbandry and Pharmaceutical Sciences of Chinese Academy of Agricultural Sciences, Lanzhou, 730050, China.
Sheep Breeding Engineering Technology Research Center of Chinese Academy of Agricultural Sciences, Lanzhou, 730050, China.
BMC Genomics. 2024 Sep 30;25(1):906. doi: 10.1186/s12864-024-10800-6.
The Tibetan sheep is one of the three major primitive sheep breeds in China, representing a unique and high-quality genetic resource in the Qinghai-Tibet Plateau and neighboring high-altitude regions, exhibiting exceptional adaptability to high-altitude climatic environments. However, research on the genetic relationships among different populations of Tibetan sheep at the whole-genome level remains insufficient. This study aims to explore the population structure and historical dynamics among 11 Tibetan sheep populations, accurately assess the genetic diversity within the populations, and providing a theoretical basis for the development of targeted genetic breeding strategies for Tibetan sheep.
In this study, a total of 10,884,454 high-quality SNPs were obtained. All Tibetan sheep populations exhibited varying degrees of linkage disequilibrium, with similar decay rates; among them, the WT population showed the fastest decay, while the TS population exhibited the slowest decay rate. Analyses using Tajima's D and π indicated that the genetic diversity levels of the Tibetan sheep populations are generally low. Fst results revealed that most populations exhibited moderate to low levels of genetic differentiation. The effective population size among Tibetan sheep populations showed an increasing trend over time. The evolutionary relationships among Tibetan sheep populations reflect the correlation between their geographical locations and genomic genetic distances, while also indirectly confirming the impact of historical activities such as early human migration, admixture, fusion, and expansion on the population sizes and distributions of Tibetan sheep.
The results indicate that the genetic diversity levels and genetic differentiation among Tibetan sheep populations are relatively low. In this study, we identified the genetic characteristics of Tibetan sheep populations, which exhibit low levels of diversity, genetic differentiation, and a strong population structure. A deeper genomic exploration of the population structure and diversity status of Tibetan sheep populations will provide theoretical support for subsequent genetic breeding and diversity conservation efforts.
藏羊是中国三大原始绵羊品种之一，是青藏高原及周边高海拔地区特有的优质遗传资源，对高海拔气候环境具有极强的适应性。然而，有关藏羊不同群体在全基因组水平上的遗传关系的研究仍不够充分。本研究旨在探讨 11 个藏羊群体的群体结构和历史动态，准确评估群体内的遗传多样性，为藏羊有针对性的遗传育种策略的制定提供理论依据。
本研究共获得了 10884454 个高质量的 SNP。所有藏羊群体均表现出不同程度的连锁不平衡，且衰减速率相似；其中，WT 群体的衰减最快，而 TS 群体的衰减最慢。Tajima's D 和π分析表明，藏羊群体的遗传多样性水平普遍较低。Fst 分析结果表明，大多数群体表现出中等至低度的遗传分化。藏羊群体的有效群体大小随时间呈增加趋势。藏羊群体的进化关系反映了其地理位置与基因组遗传距离之间的相关性，同时也间接证实了早期人类迁徙、混合、融合和扩张等历史活动对藏羊群体规模和分布的影响。
结果表明，藏羊群体的遗传多样性水平和遗传分化程度相对较低。本研究对藏羊群体的遗传特征进行了鉴定，发现其遗传多样性、遗传分化程度较低，群体结构较强。对藏羊群体的种群结构和多样性状况进行更深入的基因组探索，将为后续的遗传育种和多样性保护工作提供理论支持。
