The Genetic Diversity Of Wild And Cultivated Populations Of Cynoglossus Semilae

Cynoglossus semilae, which is mainly distributed in the coastal waters of China(including Bo sea,Yellow sea,East sea,northern of South sea),Korea,Japan and the east of Russian, is economically important .But the nature resource of Cynoglossus semilae was decline so severely in recent years that it can not but only be fished in the area of the Yellow Sea and Bohai Sea now for the reasons of excess fishing,environment pollution and so on.As the development of the technology of the artificial breeding and reproduce of Cynoglossus semilae , the pisciculture of Cynoglossus semilae was developping rapidly in the north and south of China whereas a negative impact on the genetic structure of Cynoglossus semilae may become being during the progress of aquiculture which is due to the genetic bottleneck , inbreeding depression or other factors.So we compared the genetic diversity of four populations of Cynoglossus semilae (two wild populations from Tangshan and Jiangsu and two cultured populations from Jiangsu and Fujian)with technologies of allozyme and AFLP.By this it may provide some theoretics for the genetic resource protecting and genetic breeding of Cynoglossus semilae.Results of our studies are as follows:1.Nine enzyme systems presumably encoded by 16 allozyme loci of the wild and cultivated populations of Cynoglossus semilae were investigated using the assay of vertical slab polyacrylamide gel electrophoresis:four loci(Sod-1,Adh-1,Sdh-1,Amy-2)in Tangshan population and three loci(Adh-1,Sdh-1,Amy-2)in the other three populations(JS.W,ZZ.C,HY.C)are presented polymorphic(P0.99);the average of Percentage of polymorphic loci (P),observed heterozygosity (Ho),expected heterozygosity (He),Mean effective number of alleles per locus(Ae) of wild populations is 21.275%,0.1177,0.0854, 1.1499 resepectively which is higher than the cultivated populations(18.75%,0.1156,0.0741,1.1355);genetic distance between the wild populations is 0.0006;the average genetic distance of four populations is 0.0012;a little differentiation occurs among populations (FST=0.0109,Nm=22.5850).The results indicate that : the genetic diversity of Cynoglossus semilae is in the middle level when compared with other fishs ; the genetic diversity of wild populations of Cynoglossus semilae is higher than the cultivated and the genetic divergence between Bo sea and Yellow sea is inferior.2.A total of 498 loci ,of which 279 (56.02 %)were polymorphic, were detected from 120 individuals in the 4 populations using 8 pairs of AFLP primes combinations ,The proportion of polymorphic loci , the Nei genetic diversity and Shannon genetic diversity index of the four populations are 45.18 %,0.1159,0.1817(TS .wild);39.96 %,0.1059,0.1663(JS.wild);37.95 %,0.1046,0.1629(HY.cultured);37.75 %,0.1015,0.1587 (ZZ.cultured). Genetic distance between the wild populations is 0.0665, GST is 0.2052, Nm is 1.9371.These results show that : the genetic diversity of Cynoglossus semilae is not in the high level when compared with other fishs;the gene flow between the two wild populations is high; the genetic structure of cultured and wild populations are similar according to the distributions of the frequency of dominant genes .