团头鲂高密度遗传连锁图谱的建立及性别QTL定位

Construction of a high-density genetic linkage map and QTL mapping for gender of Megalobrama amblycephala

以团头鲂自交197个F1个体为作图群体,通过RAD-Seq测序挖掘SNP分子标记,构建团头鲂最新一代高质量、高密度的遗传连锁图谱,并对性别相关QTL进行定位。结果显示,该遗传连锁图谱包括10795个SNP标记,24个连锁群,图谱全长为2578.54 cM,平均标记间隔为0.24 cM。使用MapQTL6.0软件的多QTL区间作图法,在已构建的连锁图谱上对性别QTL进行定位。取LOD值为3.0为QTL存在的阈值,共定位出4个性别相关QTL,分别位于LG8、LG12、LG15、LG18号连锁群上,单个QTL位点的LOD值范围为3.18~4.17,可解释表型变异范围为7.7%~10.0%。在团头鲂基因组内筛选QTL区间内SNP标记附近的基因,通过基因功能注释分析,筛选到一个参与生殖过程的关键候选基因DCTN2。

Megalobrama amblycephala is one of the most important herbivorous economic fish in China.In this study,hybrid F1 individuals of M.amblycephala were used as the mapping population,the high-quality and high-density genetic linkage map was constructed and sex-related QTLs(quantitative trait loci)were mapped by mining SNP molecular markers through restriction-site associated DNA sequencing(RAD-seq)technology.The result showed that the linkage map included 10795 SNPs and 24 linkage groups,with a total length of 2578.54 cM and an average marker interval of 0.24 cM.Based on the linkage map,Muliti-QTL mapping(MQM)was analyzed to fix QTLs related to gender traits by using Map QTL 6.0 software.The experiential LOD value of 3.0 was taken as the threshold for the existence of QTL tags,and 4 sex-related QTLS were located in the LG8,LG12,LG15 and LG18 linkage groups.The LOD value of each QTL ranged from 3.18 to 4.17,which explained phenotypic variation ranged from 7.7%to 10.0%.After screening genes near SNP markers in the QTL confidence interval,DCTN2,a key candidate gene,which may be involved in the reproductive process of M.amblycephala,was screened by functional annotation analysis.This research will provide a reference for the development of gendered molecular markers of M.amblycephala.