基于D-loop序列和SSR的从江田鱼与6个鲤群体的遗传分析

Genetic Diversity of Congjiang Cyprinus carpio and 6 C.carpio Populations Based on D-loop Sequence and SSR Marker

【目的】探明从江田鱼的遗传背景及其多样性水平,为进一步开展系统选育提供数据参考。【方法】采用D-loop序列和11个SSR标记开展从江田鱼(CJTY)与清水江鲤(QSJ)、太湖鲤(THL)、黄河鲤(HHL)、黑龙江鲤(HLJ)、福瑞鲤(FRL)及松浦镜鲤(SPL)等6个鲤群体的遗传分析。【结果】长度为932 bp的D-loop片段上有46个多态性位点,共定义41个单倍型,其中CJTY有16个单倍型;CJTY的核苷酸遗传多样性π值为0.005,单倍型多样性H_(d)为0.829,高于FRL和SPL,但低于其余4个鲤群体,CJTY的多态信息含量(PIC)为0.82,高于FRL(0.73)和SPL(0.50),但低于其他4个鲤群体,CJTY的期望杂合度(H_(e))为0.90,低于QSJ(0.93)和THL(0.92),高于其他4个鲤群体;遗传分化指数(F_(ST)值)显示CJTY与QSJ、THL、HHL、HLJ的分化程度较低,与FRL呈中度遗传分化,与SPL呈高度遗传分化,FRL和SPL各为1个亚群,其余5个群体为1个亚群;群体间遗传距离分析结果与F_(ST)结果相符。【结论】从江田鱼的遗传多样性水平高于2个人工选育群体(FRL和SPL),低于4个野生群体(QSJ、THL、HHL和HLJ);从江田鱼具有相对独立的地理分布区域和特定养殖模式等特点,受到一定程度自然选择或人工选择压力,但未经系统选育实践,尚保留较高遗传多样性水平,具有进一步遗传改良的潜力。

【Objective】The genetic background and diversity level of Congjiang Cyprinus carpio(CJTY)are analyzed to provide the data reference for further developing systematic breeding of Congjiang C.carpio.【Method】The genetic characteristics of CJTY and 6 C.carpio populations(QSJ,THL,HHL,HLJ,FRL and SPL)are analyzed by using D-loop sequence and 11 SSR markers.【Result】There are 46 polymorphic loci on D-loop fragment with length of 932 bp and 41 polymorphic loci are defined as haplotypes.CJTY contains 16 haplotypes.The nucleotide genetic diversity(π)and haplotype diversity(H_(d))of CJTY is 0.005 and 0.829 respectively,higher than FRL and SPL,and lower than 4 other C.carpio populations.The polymorphic information content(PIC)of CJTY is 0.82,higher than FRL(0.73)and SPL(0.50)and lower than 4 other C.carpio populations.The expected heterozygosity(H_(e))is 0.90,lower than QSL(0.93)and THL(0.92)and higher than 4 other C.carpio populations.There is a lower genetic differentiation degree between CJTY and QSJ,THL,HHL,HLJ,a moderate genetic differentiation degree between CJTY and FRL,and a higher genetic differentiation degree between CJTY and SPL.FRL and SPL are divided into the respective subgroup.CJTY,QSJ,THL,HHL and HLJ are divided into the same subgroup.The genetic distance among different C.carpio populations accords with F_(ST).【Conclusion】The genetic diversity level of CJTY is higher than 2 artificial breeding populations(FRL and SPL)and lower than 4 wild C.carpio populations(QSJ,THL,HHL and HLJ).CJTY with the advantages of relatively independent geographical distribution,the specific culture mode and higher genetic diversity level without systematic selection practice has the potential for its further genetic improvement.