| In this paper,inter simple sequence repeat(ISSR) markers were used to evaluate the genetic diversity and genetic structure within and among different natural populations of the Perciformes,included Channa argus,Siniperca chuatsi and Siniperca scherzeri.Understanding the levels of genetic diversity and genetic structure has an important theoretical guidance for the germplasm resources’ evaluation,protection and sustainable utilization.The main results of this study are as follows:(1) The orthogonal design method was used to optimize ISSR-PCR system of Perciformes in five factors(DNA template, Mg2+, primer,d NTPs and Taq DNA polymerase). It contained 60 ng template DNA in Channa argus reaction system, 2.5 mmol / L Mg2+, 0.3μmol/L primers, 0.2 mmol / L d NTPs, 0.5 U Taq DNA polymerase; and It contained 80 ng template DNA in Siniperca chuatsi and Siniperca scherzeri reaction system, 2 mmol/L Mg2+, 0.4 μmol/L primers, 0.2 mmol/L d NTPs, 0.75 U Taq DNA polymerase.and the optimal ISSR-PCR system for Perciformes was established.(2) Fifteen ISSR primers(out of 80) were selected for amplifying genomic DNA belonging to 3 populations of Channa argus. A total of 141 reproducible DNA fragments were amplified and the polymorphic locus were 53 from Channa argus group.Using POPGENE software to analysis the genetic diversity index, the percentages of polymorphic loci(PPB) in three populations were 19.86 %、25.53 % and 29.79 %, The observed numbers of alleles(Na) were 1.1986、1.2553 and 1.2979, The effective numbers of alleles(Ne) were 1.1239、1.1745 and 1.1976, The Nei’s gene diversities(h) were 0.0712、0.0976 and 0.1123, The Shannon’s information indices(I) were 0.1057、0.1428 and 0.1653, The genetic distances were 0.0628、0.0800 and 0.1016. The results showed that there was in a current level of genetic diversity in the three wild populations of Channa argus,and the level of genetic diversity in the three populations arranged in a decent order was NWWL>QHWL>DJWL.Using Shannon indices analyzed differentiation of Channa argus.The result showed that intra-populations was 76.86 %,and inter-populations was 23.14 %. The analysis of Nei’s genetic diversity revealed genetic differentiation coefficient Gst was 0.1984. The gene flow(Nm) was 2.0199 within populations.The results showed there was a larger genetic differentiation because of natural selection and population genetic differentiation mainly comed from within population.(3) Fifteen ISSR primers were used for amplifying genomic DNA belonging to 2 populations of Siniperca chuatsi.A total of 148 reproducible DNA fragments were amplified and the polymorphic locus were 79 from Siniperca chuatsi group,and the percentage of polymorphic loci was 53.38%,which showed the genetic diversity of Siniperca chuatsi was quite rich at the species level.Using POPGENE software to analysis the genetic diversity index,the PPB in two populations were 28.38% and 27.7%.The effective numbers of alleles(Ne) were 1.2022 and 1.1507.The results showed that the two populations genetic diversity remain at the medium level,but lower than the species level.the level of genetic diversity in the two populations arranged in a decent order was NWGY> DJGY.Shannon indices demonstrated that differentiation of Siniperca chuatsi were divided into two parts,47.09 % from intra-populations and inter-populations was 52.91 %.The analysis showed that strong genetic differentiation occurred among-population and within-population.According to the Nei’s genetic diversity data estimation, the genetic differentiation coefficient Gst among-population was 0.5096, gene flow Nm was 0.4812,The results showed that strong genetic differentiation occurred among-population Siniperca chuatsi.(4) Fifteen ISSR primers were used for amplifying genomic DNA belonging to 3 populations of Siniperca scherzeri.A total of 147 reproducible DNA fragments were amplified and the polymorphic locus were 83 from Siniperca scherzeri group.Using POPGENE software to analysis the genetic diversity index, PPB in three populations were 44.22 %、19.05 % and 28.57 %, Na were 1.4422、1.1905 and 1.2857, Ne were 1.2970、1.1282 and 1.1862, h were 0.1681、0.0732 and 0.1049, I were 0.2473、0.1074 and 0.1544, The genetic distances were 0.1848、0.0722 and 0.0898. The results showed that the level of genetic diversity in the three populations arranged in a decent order was NWBG > PSTBG > QHBG. Analyzed the differentiation of Siniperca scherzeri. the analysis showed that intra-populations was 60.44 %,and inter-populations was 39.56 %, the most variance were from within-population but not from among-population. According to the Nei’s genetic diversity data estimation, the genetic differentiation coefficient Gst was 0.4161. The Nm was 0.7016 within-population,and gene flow had the low level. The analysis showed that strong genetic differentiation existed in among-population of Siniperca scherzeri. |
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