| Two most important commercial species, Coilia ectenes from China and C.nasus from Japan were analyzed by using Morphology, Iisozyme and PCR techniques in order to exploit rationally the two species and sustainably utilize them. Results of the research fill up the blank in the field of the two species genetics. It is important to protect the genetics diversity of the two species.Firstly, the biological characteristics of C.ectenes from China and C.nasus from Japan populations were analyzed in this paper. Morphological characters of the two species were described in detail. The study of Morphological characters in the two species was studied through conventional measurement and statistic analysis. The result enunciated that there were significantly differences among some characters, such as scale, scutes, and vertebras and so on. The variation level was above subspecies according to 75% principle. About the measurement characters, we chose twelve variables to study the difference between C.ectenes and C.nasus. The results showed there were significant differences in the two species. By using STATISTICS software to do clustering analysis, it was found that Chinese populations cluster together and Japanese populations cluster together, respectively. Horizontal starch gel electrophoresis was applied to investigate the genetic diversity of C.ectenes from China and C.nasus from Japan populations. Three Chinese and two Japanese populations were examined in this paper. Ten enzymes (from liver and musle) revealed seventeen putative loci. A locus is considered to be polymorphic if the frequency of the most common allele does not exceed 0.99, otherwise, the locus is considered monomorphic. Among them three were polymorphic, PGM*, MPI* and MDH-1*. The results showed that PGM* locus has quite different alleles among five populations. The difference of allele frequencies was obviously at PGM*loci. The proportions of polymorphic loci were from 0.0588 to 0.1765 (P0.99). The values of observed and expected heterozygosity were from 0.0049 to 0.0381 and from 0.0126 to 0.0395 respectively. There was no replacement of alleles at all the seventeen putative loci among populations. The Nei's genetic distance among C.ectenes from China varied from 0.0000 to 0.0014. The Nei's genetic distance between C.ectenes and C.nasus populations varied from 0.0014 to 0.0054 and the Nei's genetic distance between C.nasus populations was 0.0006. The genetic distance between C.ectenes and C.nasus was much larger.The average effective numbers of allele varied from 1.0221 to 1.0977 among five populations. The genetic deviation index indicated that heterozygote was surplus at all the loci except PGM* locus of Dongying and Rugao populations. Because the index of the two populations was negative, the heterozygote was deficient. Isozyme analysis indicated that the genetic variation between C.ectenes and C.nasus populations was much larger. Compared with other marine fishes, the genetic diversity of C.ectenes and C.nasus populations was at a lower level.Finally, the Mitochondrial DNA Cytb gene fragments of C.ectenes and C.nasus were amplified and sequenced. Results of the Mitochondrial Cytb gene sequence revealed that variation was belong to intra-specific genetic difference between C.ectenes and C.nasus. No deletion/insertion was detected among Cytb gene fragments. Nucleotide composition analysis revealed that the difference of two species was no significant. By analyzing 415bp homologous sequences, we got three variable sites, and no deletion/insertion was detected. Four haplotypes were examined, in which two of them were shared by C.ectenes and C.nasus. The haplotype diversity was 0.23, and the nucleotide diversity was 0.059%. The number of average nucleotide difference was 0.24. The nucleotide composition of T, C, A, G were 30.1%, 25.3%, 29.9%, 14.7%, respectively. The net genetic distance of C.ectenes and C.nasus was 0.0006. Result of Tajma-D test and Fu`st test showed there were significant difference between C.ectenes and C.nasus. |
PDF Full Text Request