| Macrobrachium nipponense distributes widely in natural waters in China. It is also one of important freshwater spawns for aquaculture. Because of inbreeding, serious retrogression of genetic traits appeared in Macrobrachium nipponense. It's necessary to study the conservation of genetic resources and genetic improvements of Macrobrachium nipponense. This paper chiefly studied the genetic diversity of different geographic populations of Macrobrachium nipponense and its closely related species, Macrobranchium hainanense.Random Amplified Polymorphic DNA (RAPD) was applied to investigate the genetic diversity of six geographic populations of Macrobrachium nipponense, which were collected from the Weishan Lake(WL), Hongze Lake(HzL), Taihu Lake(TL), Longgan Lake(LL), Honghu Lake (HL) and Pearl River(PR). Under optimal conditions, 20 random primers from OPI, OPM, OPP, OPX, were chosen to analyze their genomic DNA (30 individuals of each population). Except OPX—08, all other primers displayed polymorphic. A total of 220 RAPD fragments ranged 100bp-2000bp were obtained, 131 of which were polymorphic (59.55%). For different populations, the proportions of polymorphic loci were 13.38%-40.00%, mean expected heterozygosity varied from 0.1485 to 0.2024, and the Shannon index (I) varied from 0.2174 to 0.2901. Index of genetic diversity Gst ranged from 0.1655 to 0.4483 for different populations, and index of genetic diversity Gsto was 0.4461. Nm ranged from 0.6154 to 2.5210. Results indicated that notable genetic divergence emerged between populations. Genetic distances between populations were 0.0336-0.1444. The genetic distances were positively correlative with the geographic distance between populations. This study was not only in favor of protecting and using of genetic resources, but also provided guides for genetic improvement and selection of breeding materials.Macrobranchium nipponense (?) were crossed with Macrobranchium hainanense (?)... |
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