长江中游水系鲢和草鱼群体mtDNA遗传变异的研究

MITOCHONDRIAL DNA VARIATIONS OF SILVER CARP AND GRASS CARP IN POPULATIONS OF THE MIDDLE REARCHES OF THE YANGTZE RIVER REVEALED BY USING RFLP-PCR

采用 PCR技术进行了长江中游鲢和草鱼四个地理群体的线粒体 DNA(mt DNA)限制性片段长度多态性 (RFL P)的研究。四个地理群体包括长江中游的湖北嘉鱼和江西瑞昌两个地理群体 ,长江中游的两大支流汉江和湘江群体。 PCR技术扩增出 mt DNA ND5 - ND6基因 ,选用 1 0种限制性内切酶对 PCR产物进行酶切。从鲢中共检出 1 8种单倍型 ,在草鱼中没有发现多态现象 ,只有一种单倍型存在。进一步地证实了长江鲢的遗传多样性比草鱼的要丰富得多 ,与这两种鱼类在长江现有生物量成反比的反常现象。

Silver carp ( Hypophthalmichthys molitrix ) and grass carp ( Ctenopharyngodon idellus) are the most important farmed fishes in China. The seedlings of said species for aquaculture have come directly and indirectly from the Yangtze River because germplasm resources of silver carp and grass carp in the Yangtze River is superior to those of other rivers. Therefore, genetic resources of silver carp and grass carp in the Yangtze River play a very important role in fisheries development in China in the long run. In present study, mitochondral DNA variations were screened in four populations of the middles reaches of the Yangtze River by using PCR RFLP method. The four populations include two populations, namely, Jiayu and Ruichang which are from the middle reaches of the Yangtze River, and the other two populations, namely, Han River and Xiang River which are from two branches of the middle reaches of Yangtze River. Eighteen haplotypes in silver carp are detected using ten restriction enzymes, including Rsa Ⅰ, Hae Ⅲ, Hinf Ⅰ, Hpa Ⅱ, Dde Ⅰ, Taq Ⅰ, Nci Ⅰ, Alu Ⅰ, Ava Ⅱ and Hinc Ⅱ. However, no genetic variation is noted in grass carp by using same enzymes. Obviously, the genetic diversity in grass carp is much poor than that of silver carp in the middle reaches of the Yangtze River. The genetic diversity and biomass has negative relation, which is not consistent with most cases.