Molecular Population Genetics Group, Temasek Life Sciences Laboratory, National University of Singapore, 117604 Republic of Singapore.
BMC Genomics. 2010 Feb 24;11:135. doi: 10.1186/1471-2164-11-135.
Grass carp (Ctenopharyngodon idella) belongs to the family Cyprinidae which includes more than 2000 fish species. It is one of the most important freshwater food fish species in world aquaculture. A linkage map is an essential framework for mapping traits of interest and is often the first step towards understanding genome evolution. The aim of this study is to construct a first generation genetic map of grass carp using microsatellites and SNPs to generate a new resource for mapping QTL for economically important traits and to conduct a comparative mapping analysis to shed new insights into the evolution of fish genomes.
We constructed a first generation linkage map of grass carp with a mapping panel containing two F1 families including 192 progenies. Sixteen SNPs in genes and 263 microsatellite markers were mapped to twenty-four linkage groups (LGs). The number of LGs was corresponding to the haploid chromosome number of grass carp. The sex-specific map was 1149.4 and 888.8 cM long in females and males respectively whereas the sex-averaged map spanned 1176.1 cM. The average resolution of the map was 4.2 cM/locus. BLAST searches of sequences of mapped markers of grass carp against the whole genome sequence of zebrafish revealed substantial macrosynteny relationship and extensive colinearity of markers between grass carp and zebrafish.
The linkage map of grass carp presented here is the first linkage map of a food fish species based on co-dominant markers in the family Cyprinidae. This map provides a valuable resource for mapping phenotypic variations and serves as a reference to approach comparative genomics and understand the evolution of fish genomes and could be complementary to grass carp genome sequencing project.
草鱼（Ctenopharyngodon idella）属于鲤科，该科包括 2000 多种鱼类。它是世界水产养殖中最重要的淡水食用鱼类之一。连锁图谱是绘制目标性状图谱的重要框架，通常是了解基因组进化的第一步。本研究旨在利用微卫星和 SNP 构建草鱼第一代遗传图谱，为经济重要性状的 QTL 作图生成新资源，并进行比较作图分析，以深入了解鱼类基因组的进化。
我们构建了草鱼第一代连锁图谱，图谱面板包含两个 F1 家系，共 192 个后代。24 个连锁群（LG）中定位了 16 个基因中的 SNP 和 263 个微卫星标记。LG 的数量与草鱼的单倍体染色体数相对应。雌性和雄性的性连锁图谱分别长 1149.4 和 888.8 cM，而平均性连锁图谱长 1176.1 cM。图谱的平均分辨率为 4.2 cM/标记。将草鱼标记的映射序列与斑马鱼全基因组序列进行 BLAST 搜索，发现草鱼和斑马鱼之间存在大量的宏同线性关系和广泛的标记共线性。
本文构建的草鱼连锁图谱是鲤科中第一个基于共显性标记的食物鱼类连锁图谱。该图谱为绘制表型变异提供了有价值的资源，并可作为比较基因组学的参考，以了解鱼类基因组的进化，可与草鱼基因组测序项目互补。
