大头鲤原种种群的遗传现状

Genetic Status of the Original Population of Barbless Carp Cyprinus pellegrini

大头鲤(Cyprinus pellegrini)是一种云南高原湖泊特有的国家Ⅱ级重点保护鱼类。土著种大头鲤与外来种鲤(C.carpio)的渐渗杂交在星云湖野生种群中已经广泛发生。本研究结合形态和微卫星及线粒体DNA分析检测了螺蛳铺大头鲤原种种群的遗传现状。结果显示,螺蛳铺大头鲤样本所有个体在形态上位于大头鲤与鲤的参照样本之间;在微卫星因子对应分析中也显示,其位于大头鲤与鲤的参照样本之间,但与大头鲤参照样本较为相似;在线粒体DNA分析中显示,都具有鲤的单倍型。中间性形态特征以及核基因组成与线粒体基因组成的不一致现象,表明螺蛳铺大头鲤样本均为杂种个体。因此,螺蛳铺大头鲤原种种群可能是一个杂种种群,有必要重新建立大头鲤人工繁殖计划。

Barbless Carp （Cyprinus pellegrini）, which is endemic to lakes of Yunnan plateau, is categorized into the second grade in the list of China key protected animal species. Introgressive hybridization between native Barbless Carp and exotic Common Carp （C. carpio） has occurred extensively in Xingyun Lake. This study assessed the genetic status of the Luosipu original population of Barbless Carp based on morphological, microsatellite and mitochondrial I）NA analyses. Morphological analyses showed that all individuals of the Luosipu Barbless Carp sample were strictly intermediate between reference samples of Barbless and Common Carp. Factorial correspondence analysis of microsatellite data indicated that all individuals of the Luosipu Barbless Carp sample fell in between reference samples of Barbless and Common Carp, but were very near to the former. Mitochondrial DNA analysis revealed that all individuals of the Luosipu Barbless Carp sample had the mitochondrial DNA haplotypes of Common Carp. There was obvious inconsistency between nuclear and mitochondrial genetic structures in Luosipu Barbless Carp sample. These results suggest that all individuals of the Luosipu Barbless Carp sample are hybrids. Considering that the Luosipu Barbless Carp population may in fact be a hybrid population, a new captive breeding programme should be found for effectively conserving and restoring Barbless Carp.