菲律宾蛤仔高密度遗传图谱构建及重要经济性状QTL定位

A genetic linkage map is a powerful tool for identifying quantitative trait loci (QTL) and cloning trait related genes. In aquaculture species, mapping of economically important QTLs can lead to genetic improvement through marker-assisted selection. The Manila clam (Ruditapes philippinarum) is a maricultured bivalve species with important commercial value. The shell colour and decorative pattern is heritable to the offsprings, which is closely associated with growth, stress resistance and other economic traits. Due to a small number of microsatellites is currently available, and genetic linkage map has not been constructed in R. philippinarum, now it is impossible to launch the marker-assisted selection program in this species. In this project, we would develop a large amount of microsatellite markers in R. philippinarum, construct genetic linkage map based on microsatellites, and locate shell colour and growth-related QTL. The identification of genetic markers associated with growth-related traits provides the scientific basis for gene discovery, gene regulation and marker-assisted selection. This project would be conducive to whole genome assembly of R. philippinarum, and have great significance for facilitating functional genomics analysis, positional candidate cloning of QTLs and marker-assisted selection.

构建遗传连锁图谱，结合数量性状遗传研究，开展数量性状QTL定位和分子标记辅助选择是水产动物遗传育种研究的一个重要领域。菲律宾蛤仔（Ruditapes philippinarum）是我国沿海滩涂养殖的重要经济贝类。其变异丰富的壳色花纹可以遗传给后代，且与生长、抗逆等经济性状密切相关。针对菲律宾蛤仔现有微卫星标记数目较少，遗传图谱尚未构建，难以满足分子标记辅助育种要求等问题。本项目拟开发大量菲律宾蛤仔的微卫星标记，构建菲律宾蛤仔高密度遗传连锁图谱，并对壳色与生长相关性状进行QTL 定位。筛查与生长、壳色相关的遗传标记，为基因发掘、基因调控和分子标记辅助育种提供科学依据。项目研究将有助于菲律宾蛤仔基因组序列的拼接，对促进菲律宾蛤仔功能基因组学、重要经济性状相关基因图位克隆和分子标记辅助选择育种等研究具有重要意义。

菲律宾蛤仔是我国重要的海水养殖贝类。高密度遗传连锁图谱是进行遗传学和基因组学研究的必不可少的工具。随着测序分型技术的发展，高密度遗传图谱的构建能够在基因组资源匮乏的海洋生物中得以实现。在本研究中，我们首次开展了重要经济贝类菲律宾蛤仔的高密度遗传图谱构建和经济性状的QTL定位研究。在雌雄整合图谱中，共9658个标记定位于18个性别平均连锁群，覆盖长度为1926.98 cM。基因高密度遗传图谱，我们定位了10个与壳长、壳宽、壳高和体重等生长性状及壳色的背景色和条纹相关的QTL。我们构建的高密度图谱有效的对分离性状进行了QTL检测，发现了2个QTL位置与最相近的标记一致。在本项目支持下完成的高密度遗传图谱揭示了基因组的基本结构特征，对于进一步开展菲律宾蛤仔和其它双壳贝类的比较基因组研究、基因组拼接组装、遗传性状改良和新品种培育奠定了重要基础。