ISSR Genetic Diversity Of Four Major Chinese Carps In Poyang Lake And Its Original Rivers

Poyang Lake is the largest freshwater lake in China. It swallows water from five major rivers in Jiangxi province including Gan-River, Fuhe-River, Xin-River, Rao-River and Xiu-River. Four major Chinese carps (black carp, grass carp, silver carp and bighead carp) are all very important aquatic resources in the Yangtze River. The protection and utilization of germplasm resources of them has a direct impact on the sustainable development of freshwater fisheries in China. However, although four major Chinese carps are widely distributed in the Poyang Lake and its'original rivers, no scholars have down systemic researches of the biological diversity and difference on them up to now.As to fill in the blank of four major Chinese carps in the Poyang Lake and its original rivers, and also in the aim of adding theoretical basis of the characteristics of four major Chinese carps, this research using ISSR molecular markers to study and analyze the genetic diversity of four major Chinese carps in Hukou area of Poyang Lake. Genetic diversity comparison and analysis of grass carp, silver carp and bighead carp in Gan-River, Xin-River, Fuhe-River, Xiu-river and Hukou area. The main results are:(1) Using ISSR-PCR marker (random primers) to analyze the genetic diversity of four major Chinese carps. The results showed that five primers generate 38 loci in black carp, the percentage of polymorphism is 86.63%, the effective number of alleles is 1.479, Nei's gene diversity is 0.2831, Shannon's Information index is 0.4210; Six primers generate 46 loci in grass carp, the percentage of polymorphism is 98.33%, the effective number of alleles is 1.7308, Nei's gene diversity is 0.4016, Shannon's Information index is 0.5792; Five primers generate 38 loci in silver carp, the percentage of polymorphism is 58.19%, the effective number of alleles is 1.4166, Nei's gene diversity is 0.2350, Shannon's Information index is 0.3426; Five primers generate 47 loci in bighead carp, the percentage of polymorphism is 63.83%, the effective number of alleles is 1.4051, Nei's gene diversity is 0.2335, Shannon's Information index is 0.3467. The micro-satellites of four major Chinese carps are main two-base cycled sequence. The grass carp showed very high polymorphism which is unusual.(2) Using ISSR-PCR marker (random primers) to analyze the genetic diversity of grass carp, silver carp and bighead carp in six areas of Poyang Lake and its original rivers. The results showed that five primers generate 44 loci in grass carp, the percentage of polymorphism is 79.55%, the effective number of alleles is 1.5457, Nei's gene diversity is 0.3134, Shannon's Information index is 0.4604; Seven primers generate 63 loci in silver carp, the percentage of polymorphism is 88.89%, the effective number of alleles is 1.6613, Nei's gene diversity is 0.3691, Shannon's Information index is 0.5355; Four primers generate 47 loci in bighead carp, the percentage of polymorphism is 63.83%, the effective number of alleles is 1.5479, Nei's gene diversity is 0.3058, Shannon's Information index is 0.4446. The results index that grass carp, silver carp and bighead carp in Poyang Lake and its original rivers have high levels of genetic diversity and large differentiation among species. Caculatited genetic identity and distance between different populations of grass carp, silver carp and big head carp from different regions of Poyang Lake. The dendrograms of different populations were painted respectively by software UPGMA.