摘要
表达序列标签(Expressed sequence tag,EST)标记在基因组作图和分子标记辅助育种研究中具有重要价值。筛选和开发可用于遗传作图的鲤鱼多态性EST标记,对研究鲤鱼的基因组结构、遗传多样性研究和遗传育种有重要意义。本研究根据GenBank数据库中鲤鱼EST序列设计了67对EST引物,有47对在鲤鱼基因组DNA中成功扩增得到稳定的特异性条带,经单链构象多态性(SSCP)分析,12对(25.5%)引物扩增的EST在1个鲤鱼回交家系中具有多态性,其中6个为鲤鱼功能基因,5个与斑马鱼(Danio rerio)功能基因具较高相似性,1个与斑点叉尾(Ictaluruspunctatus)功能基因具较高相似性。这些多态性的EST在鲤鱼二倍体家系和单倍体群体中的等位基因分离均符合孟德尔规律(1∶1或3∶1),单倍体中的SSCP条带数目为二倍体的二分之一。选用其中4对多态性的EST引物对洞庭湖鲤鱼进行初步群体遗传分析,结果显示基因多样性(H)为0.437,远低于微卫星标记所揭示的该群体基因多样性(接近于1)。结果表明,多态性的EST-SSCP标记尽管遗传变异性较低,但是作为来源于编码区的Ⅰ型遗传标记,在遗传作图和种群遗传适应性等研究中有较好的应用潜力。
Expressed sequence tags （ESTs） are of high value in genome mapping and marker-assisted selection （MAS）. This study aims to develop EST markers for genome mapping and other studies of common carp （ Cyprinus carpio L）. A total of 7381 EST sequences （400-3500bp） were downloaded from the EST database of the GenBank as the source data of the present analyses. Sixty-seven pairs of primers （designated as HB1-67） were designed in the 3＇ untranslated region （UTR） of the common carp ESTs ,47 of which can successfully amplify specific products from genomic DNA. Twelve polymorphic EST markers were identified in a backcross mapping family of common carp by single-strand conformation polymorphism （SSCP） analysis. Six of the 12 polymorphic EST markers were derived from common carp genes of known function, and the rest were from common carp ESTs homologous to putative genes in zebrafish （ Danio rerio ） or channel catfish （ lctalurus punctatus ）. Allele distribution of these polymorphic EST markers was found to follow the Mendelian segregation （ 1 ： 1 or 3 ： 1 ） in both the backcross family and gynogenetic haploids, and the number of SSCP bands in haploid population was half of that in diploid family. The gene diversity （ H = 0.437） of Dongting Lake population of common carp revealed by 4 polymorphic EST markers is much lower than that by previous microsatellite analysis （close to 1 ） . The results of present study indicated that EST-SSCP markers, with codominant inheritance, can be used as a powerful tool in the genetics of not only diploid but also haploid common carp. As Type I marker derived from coding region with relatively lower genetic variability, EST-SSCP markers are still of high potentials in such studies as genome mapping （ including genetic linkage maps and gene maps, as well as comparative mapping）, genetic structure, and genetic adaptability of fish populations.
出处
《水生生物学报》
CAS
CSCD
北大核心
2008年第2期207-212,共6页
Acta Hydrobiologica Sinica
基金
“973”项目(3004CB117405)
湖北省创新群体(3004ABC005)
国家自然科学基金(30490234)资助
关键词
鲤鱼
EST标记
遗传图谱
单链构象多态性(SSCP)
Common carp （ Cyprinus carpio L. ）
Genome mapping
Expressed sequence tag （EST）
Single-strand conformation polymorphism （SSCP）
