黄河鲤生长性状动态QTL定位及分析

Growth is one of the most important genetic traits in fish, which is determined by genetic, environmental and interaction of genetic and environmental. To date, researchers have reported a lot of studies about molecular mechanism and QTL mapping of fish growth. However, there is a few studies on dynamic QTL mapping of growth traits have been reported. In the project, Yellow River carp (Cyprinus carpio haematopterus Temminck et Schlegel) is as research subject to construct high-density genetic linkage map and map growth-related QTLs. First, we establish families and mark them with passive integrated transponder (PIT) when average body length is 10 cm. After marking, seven traits (total length, body length, body weight, body depth, body width, head length and caudal length) are measured every two months. After confirming the reference family according to the measurements, SLAF-seq is employed to explore polymorphic SNP and genotype mapping population. Then, the genetic linkage map is constructed by HighMap software. According to the information of these growth traits and linkage map, we can map dynamic QTLs by WinQTL Cart2.5 software. The objects of the study are to acquire a high-density genetic linkage map and map more than 50 dynamic QTLs. The results not only expound action model of dynamic QTLs in growth and development, but also provide research ideas and theories for growth molecular mechanism and marker-assisted breeding.

生长是鱼类遗传育种研究的重要性状之一，它主要受基因、环境以及基因与环境互作等三方面因素的影响。目前，人们在鱼类生长性状的分子机制和相关QTL定位方面开展了大量研究，但是与生长发育相关的动态QTL研究较少且不系统。本项目以黄河鲤为研究对象，通过建立黄河鲤作图家系，利用被动整合雷达标对其进行电子标记，通过定期测量生长性状，统计每条鱼的全长、体长、体重、体高、体宽、头长和尾鳍长等7个指标在不同生长阶段的表型值。根据测量结果，确定作图家系，然后通过简化基因组测序技术发掘多态SNP标记并对作图家系进行分型，利用HighMap软件构建遗传连锁图谱并对生长性状动态QTL进行定位分析。本研究将获得由SNP标记构建的黄河鲤高密度遗传连锁图谱一张，定位50个以上不同发育阶段和发育阶段间的QTL，阐明动态QTL在生长发育中的作用模型，为研究黄河鲤生长发育机制和分子标记辅助育种提供理论依据和研究思路。

黄河鲤是我国黄河流域重要的养殖鱼类。然而，随着黄河鲤养殖业的不断发展，黄河鲤的生长、抗逆等性状都出现了不同程度的衰退，亟需选育高产抗逆新品种以促进黄河鲤养殖业的健康发展。本研究通过建立黄河鲤家系，并在其体长10cm左右的时候注射PIT标记，分别在4月龄、9月龄、13月龄和17月龄时测量家系的体质量、体长、体高及体厚，17月龄测量之后剪取鳍条通过GBS技术对黄河鲤进行了遗传连锁图谱构建和生长性状的条件和非条件QTL定位。最终构建了一个黄河鲤高密度遗传连锁图谱，该图谱包含50个连锁群，10286个SNP标记，图谱总长为3474.01 cM，标记平均间距为0.35 cM，连锁群平均长度为69.48 cM。由于4月龄和9月龄的生长性状差别不显著，因此本研究未对9月龄的生长性状进行QTL定位。通过对4月龄、13月龄、17月龄3个阶段生长性状的非条件QTL和4~13月龄、4~17月龄、13~17月龄3个阶段生长性状的条件QTL进行了定位，共定位了708个QTLs，其中体质量、体长、体高和体厚相关QTLs位点分别为 152个、193个、280个和83个。研究发现影响不同时期黄河鲤生长的QTL差别较大，有些位点同时存在于多个时期，有些位点只存在于某个时期，研究结果有助于进一步解析黄河鲤的生长发育机制并为黄河鲤生长性状的分子标记辅助育种提供依据。