Research Of Morphological And Genetic Variation Of Coilia Nasus In Different Lakes

Using morphology method and DNA sequence data from the mitochondrial D-loop region, the morphological differences and genetic structure for populations of C. nasus in different lakes were studied. It is important to provide the theoretical basis with resources protection and reasonable development of C. nasus.The major findings were summarized as follows:1. Morphology analysis of Coilia nasus populations in different lakes Multivariate analysis methods were adopted to research 8 measurable characters and 20 truss network of Coilia nasus populations in three lakes in China.The ANOVA analysis found that some morphological characters had significant differences between different populations.The difference coefficient test found that all the difference values of morphological parameter were less than 1.28 , did not met the criteria into sub-species. Principal component analysis showed that all traits could be divided into 9 kinds of factors, and the cumulative contribution ratio was 83.24% , first three principal components mainly reflected the morphological differences of head and dorsal fin in different populations . Scatter plot of principal component revealed that three populations can not be distinguished.the clustering result showed that the population distance between SD and HZ was nearest,they clustered as the first groups, and then clustered with TH as the second groups. The discriminant functions of the three groups were established by six traits,and the total discriminant accuracy reached 74.5%.2. The genetic composition analysis of Coilia nasus populations in different lakesThe mitochondrial DNA control region marker was used to analysis the sequence of Coilia nasus populations in different lakes. The genetic variation and composition of Coilia nasus populations in different aqustorium were researched. It showed that the average contents of A,T,C and G bases in C. nasus populations were 33.31%, 33.31%, 19.03% and 14.28%,respectively.The content of A+T was twice as much as that of G+C. the result explained the mitochondrial DNA control region of Coilia nasus was rich in A+T, revealed the significant bias quality of base compositon.The gene diversity of different Coilia nasus populations were between 0.9111 and 0.9778. The nucleotide diversity of different Coilia nasus populations were between 0.0032 and 0.0086,explained that the composition of diversity was high in Coilia nasus populations. Twenty-two haplotypes were identified by mitochondrial DNA sequencing, and the molecular tree constructed by method UPGMA showed the individuals of the different populations couldn't be clustered as one independent group and mixed to each other.