黑龙江和乌苏里江唇的微卫星引物筛选及群体遗传结构

Screening of microsatellite primers and population genetic structure of Hemibarbus labeo in Heilongjiang River and Wusulijiang River

利用鲤(Cyprinus carpioL.)(20对引物)和Hemibarbus mylodon(21对引物)共41对微卫星引物对黑龙江(逊克,XK)和乌苏里江(虎头,HT;海青,HQ)的3个野生唇(Hemibarbus labeo)群体进行引物适合性研究,并将获得的多态性微卫星位点用于唇群体遗传结构分析。引物筛选结果表明,5对鲤引物可对唇扩增出条带,但产物均无多态性;11对H.mylodon引物能在唇中成功扩增,10对引物(10个位点)的扩增产物具有多态性,其中7个位点为高度多态(PIC>0.5)。对3个唇群体进行遗传多样性分析,结果显示10个位点的平均杂合度为0.4834,共检测到96个等位基因(40个有效等位基因),以HT群体的遗传变异水平最高。卡方检验结果表明,8个位点在3个群体中不同程度地偏离遗传平衡(P<0.05),且偏离平衡的位点均表现为杂合体缺失(Fis>0)。3个群体两两间具有较多的基因交流(Nm>11),以XK和HQ间最高(17.27),二者的遗传距离也最近(0.0497),群体间的遗传分化微弱(Fst=0.0236)。以上结果表明,H.mylodon的微卫星引物适合于唇的群体遗传变异研究。黑龙江和乌苏里江的野生唇资源受人为及环境因素的影响较大;3个群体间的遗传分化不明显,乌苏里江的HT群体更适合在人工繁殖计划中利用。

In this study, among 41 pairs of primers tested for the cross-species amplification in Hemibarbus labeo, 20 pairs were chosen from primers of Cyprinus carpio and 21 pairs were desigened from sequences of flanking microsatellites of Korea Hemibarbus mylodon. The results showed that 16 primers amplified successfully. Among them, 5 loci from C.carpio primers didn＇t show polymorphism, while 10 polymorphic loci were detected by using 11 primers from H.mylodon. Furthermore, the 10 polymorphic loci were used to evaluate the genetic variety of 3 H.labeo populations （XK, HT and HQ） which were sampled from Xunke segment in middle region of Heilongjiang River, Hutou （upstream） and Haiqing segment （downstream） in Wusulijiang River respectively. The results demonstrated that 7 loci had high polymorphism （PIC〉0.5） and the average heterozygosity of the 10 polymorphism loci was 0.483 4. In addition, total of 96 alleles （40 effective alleles） were detected in the 10 loci. Higher genetic variation level was found in HT population than in XK and HQ. The Hardy-Weinberg Equilibrium （HWE） analysis showed that 8 loci deviated from genetic equilibrium to different extents in 3 populations, and heterozygote deficiency occurred at all the 8 loci （Fis〉0）. Among the 3 populations, high gene flow was examined between populations （Nm〉 11 ）, and the highest gene flow was between XK and HQ populations （17.27） with closest genetic distance （0.049 7）. No significant genetic differentiation among populations （Fst=0.026） was detected. The present results indicate that for cross-species in H.labeo, primers from H.mylodon are more efficient and suitable than those from C.carpio which is probably due to the closer relationship between H.mylodon and H.labeo than that between C.carpio and H.labeo. The genetic structures of 3 wild H.labeo populations in Heilongjiang River and Wusulijiang River were analyzed successfully using these polymorphic loci screened from H.mylodon. These polymorphic markers from H.mylodon microsatellites will shed light on the future genetic condition investigation of H.labeo. [Journal of Fishery Sciences of China, 2008, 15 （2） ： 230-236]