| Acanthopagrus schlegelii is a fine variety of mariculture,which is in high economic value.Suffering from the overfishing,environmental pollution and other issues,germplasm resources of this fish has a change of declined.Although the succession of stock enhancement has a certain effect on the recovery of the germplasm resources of A.schlegelii,and benefit much in economic and ecological fields,the genetic diversity and population differentiation of wild species has been changed.In this study,the microsatellite markers was developed by using the method of FIASCO,and then using the developed microsatellite polymorphism markers to studied the genetic diversity and population structure of 10 populations.This study is a good complement on study of population genetics of A.schlegelii.The results are as follows:The microsatellite DNA sequences of black sea bream were enriched by FIASCO method combined with biotin-labeled probe.Randomized selection of 180 positive clones were selected for sequencing,and 157 of the 180 clones containing STRs.72 pairs of primers were designed and amplified in 30 individuals of Zhangpu population.17 pairs of polymorphic primers and 12 pairs of monomorphic primers were obtained.The number of a lleles of these polymorphic primers were 2-5,with an average of 3.3529.The mean value of polymorphic information content was 0.5133,and the range was between 0.2280 and 0.7320.The observed heterozygosity and expected heterozygosity varied from 0.0952 to 0.8966 and 0.1823-0.7407,respectively,and the mean values were 0.5239 and 0.4944.Nine polymorphic microsatellite loci were screened from those 17 loci to detect the genetic diversity and genetic differentiation of 10 A.schlegelii populations in China coastal areas.The results showed that the PIC values of these 10 populations were from 0.4433-0.5804 with an mean of 0.5143.the average number of alleles per locus ranged from 3.0000 to 3.4444,with the average and overall values of 3.2333 and 3.6667,respectively.The mean allele values were in the range of 2.0130 to 2.6014,with an average of 2.2994 and an overall value of 2.8013.Similarly,the range of observed and expected heterozygosity was 0.4607-0.5789 and 0.4657-0.5967,with an average of 0.5278 and 0.5183,and the overall values were 0.5261 and 0.6224 respectively.The Fis value is-0.0371,indicating that these populations showed to be heterozygous excess.Considering with A,Ae and PIC,the genetic diversity of these populations was moderate,and it seemed much lower when comparing with the foreign groups.The total population fixation index(Fit)in the results of genetic differentiation indicated an inbreeding phenomenon in the whole populations.The population differentiation turned to be significant,and most of the variation came from the inside of the populations.On the other hand,it showed a differentiation pattern between the north and south groups,and was not significant in the southern group as there existed a phenomenon of inconsistent with geographical distribution,which may due to the human activities.This research on the 10 coastal populations of A.schlegelii is of great significance to the breeding and germplasm of the A.schlegelii in the actual production. |
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