利用全基因组测序手段解析藏鸡高原适应的遗传机制

Adaptation is central to the evolution of species, and domestic animals provide a crucial source and model to study the process of evolution. Tibetan chicken, as one of the excellent high-land chicken breed in our country. Out of the lengthy domestication and artificial selection processes, Tibetan chicken has acquired excellent adaptation to hypoxia, low atmospheric pressure，cold temperatures and high ultraviolet radiation in Tibet. Our previous research showed that Tibetan chicken has a more complex population history than previous thought (MBE, 2015). Because of limited number of sample and their ranges, as well as low coverage of genomic sequencing data, we have not clarified the genetic structure and genetic basis of adaptation to high-land for this model chicken. In this research, we try to use a larger scale genome-wide sequencing data to clarify such issues for Tibetan chicken. We aim to perform whole genome resequencing for 80 Tibetan chickens and integrate 504 our sequenced genomes for domestic chicken and Red junglefowl, and then apply bioinformatics, population genomics and biological experimentation to elucidate the population structure and genetic basis of adaptation to high-land in Tibetan chicken.

适应性是物种进化的核心，而家养动物是研究进化的良好模型。藏鸡作为我国著名的高原鸡种，经过长期的自然和人工选择作用，对高原低氧、低压和严寒等极端恶劣环境表现出很强的适应性。前期我们对11只藏鸡进行低覆盖度的基因组测序分析，发现藏鸡群体遗传结构复杂（MBE，2015）。由于前期研究所用的样本量少，分布范围狭窄，以及基因组测序数据覆盖度低，未能对藏鸡的群体结构和适应高原的遗传机制进行全面阐述，没有锁定与其高原适应关键的基因。本研究拟对广泛分布的80只藏鸡进行基因组测序，并整合实验室产生的504只家鸡和红原鸡的基因组数据，利用生物信息学、群体基因组学和功能实验等方法来解析其群体结构特征和高原适应的分子机制。

藏鸡是我国著名的高原鸡种,对高原低氧、低压和严寒等极端恶劣环境表现出很出色的适应性。为了研究藏鸡适应高原环境的遗传机制，我们选取了西藏林芝、日喀则、山南和拉萨等地共101只藏鸡进行全基因组测序。将此数据整合到我们“1K家鸡基因组”项目的数据中，针对藏鸡进行了群体基因组分析。我们解析了家鸡和藏鸡的起源和驯化历史，比较和探讨了藏鸡和其它鸡的群体结构、进化历史和遗传多样性和遗传负载的差异。通过全基因组选择扫描发现了一些和藏鸡高原适应相关的正选择基因，其中EGLN1和RYR2在藏鸡基因组中拥有很强的选择信号。我们针对EGLN1-R289C和RYR2-R2787Q进行了细胞和小鼠水平的点突变试验和低氧环境下的功能研究。结果表明EGLN1和RYR2在藏鸡高原低氧适应有重要的作用。我们的研究不仅有利于探索家鸡如何适应新环境，更有助于培育和改良适应高原的高产品种。