扬子鳄环境适应的MHC多样性

项目名称： 扬子鳄环境适应的MHC多样性

项目编号： No.31470439

项目类型： 面上项目

立项/批准年度： 2015

项目学科： 生物科学

项目作者： 朱英

作者单位： 浙江大学

项目金额： 87万元

中文摘要： 扬子鳄全基因组层面上的外显子杂合度和内含子杂合度尚处于相同水平，表明物种仍然未摆脱瓶颈效应的影响（Cell Research,2013，23:1091）。然长久以来，种群遗传多样性低和近亲繁殖严重的瓶颈效应虽已导致尾部畸形问题，但迄今却并未出现高疾病致死率的环境适应性衰退问题。有鉴于全基因组测序技术难以分离确认MHC位点而建立环境适应性探索的功能性分子标记系统，本项目拟在业已完成了扬子鳄基因组BAC文库构建的基础上，进一步通过构建MHC基因组物理图谱及图谱克隆测序、基因注释，MHC基因组组装、位点分离与确认等研究工作，解析MHC的基因组结构，并完整地建立扬子鳄I、II类MHC位点的分子标记系统。继后，通过I、II类MHC分子标记的群体检测分析，自环境适应性免疫功能基因家族的基因组结构和多态性变异等视角，探索扬子鳄适应环境的分子机制这一科学问题。

中文关键词： 扬子鳄；环境适应；MHC结构特征；多样性

英文摘要： Genome-wide single nucleotide polymorphisms (SNPs) of the Chinese alligator (Alligator sinensis) demonstrate that this endangered reptile possesses a nearly identicial level of SNP heterozygosity in intronic regions to that in coding sequences (exons)(Cell Research, 2013, 23: 1091), which indicates that the Chinese alligator has undergone a substantial decrease in the effective population size and has resulted in an extremely low level of genetic diversity. However, the bottlenecked Chinese alligator has not shown declines in its adaptive quality, such as high rates of infection and mortality, making it interesting to determine Alsi-MHC genomic structure and adaptive diversity patterns at different MHC loci. Since the whole-genome sequencing of the Chinese alligator has failed to assemble the Alsi-MHC partial genome, which resulted from a great number of MHC gene copy and high sequence similarities among MHC loci, this project will build a physical map for the Alsi-MHC region based on a ready-to-use BAC (Bacterial Artificial Chromosome) genomic library of the Chinese alligator and identify all of Alis-MHC class I and II loci by BAC clone sequncing. Then, this project will develop multiple suites of locus-specific MHC genotyping techniques and examine adaptive variation patterns of different alligator populations. Finally, this project will explore molecular mechanisms of environmental adaptation in the Chinese alligators from the perspectives of genomic structure and allelic polymorphism.

英文关键词： Chinese alligator;environmental adaptation;MHC genomic structure;genetic variation