| The goitered gazelle,Gazella subgutturosa, also called parian gazelle, is typical median sized animal that inhabited in arid and semi-arid areas, which belongs to Gazella genus, subfamily of Antilopinae, Bovidae family and order of Artiodactyla. In 1989, it is also entered in the list of Wild Animal Protection Law of China as Category II protection species. In recent decades, the population numbers have been drastically dropped because of the habitat loss and fragmentation, excessive hunting, poaching and the increases in human population and human activities. In this study, the phylogenetic relationship, gene diversity and genetic structure of the Gazella subgutturosa four geographic populations in Xinjiang Uyghur Autonomous region were evaluated based on the cytochrome b(Cyt b) gene sqeunces as genetic marker. It is hoped that the work in this study would provide a genetic information for the classification of subspecies in Gazella subgutturusa in the world whide, meanwhile it has significances to management and protection of Gazella subgutturusa in Xinjiang.In this study overall 113 samples, 94 fecal samples and 19 muscular samples, were collected from 16 sampling sites in Gazella subgutturusa distributed areas in Xinjiang. The results in this study showed that the length of mtDNA Cyt b in 113 individuals of Gazella subgutturosa was varied from 1016 bp to 1161 bp, mean of 1124 bp. Through maching, alignment and cutting, finally 995 bp fragments of Cyt b analytic sequences were determined. In this analytic sequencs, 21 variable sites, all were single variable site, were defined with 13 Parsimony informative sites. The average A, T, G and C contents in Cyt b were 31.4%, 26.6%, 13.2% and 28.84%, respectively. The contents of A+T(58.0%) are higher than G+C(42.0%).Mutations in all 19 haplotypes were all transitional and transversional variations, and indels were not found. Among mutationobserved in these sequences there are 20 transitions and only one transversions within 21 variable sites, and the main substitution type was transition.The results of sequence analysis in four geographic populations indicated that 19 haplotypes out of 113 samples from four populations were observed. Among them, JBP populations has 5 haplotypes and TKP populations has 8 haplotypes, NTP populations and STP population have 4 haplotypes and 8 haplotypes, respectively. Among them five haplotypes were shared between each geographic population :HAP-1 was shared between TKP Population and NTP population, while HAP-2, HAP-4 and HAP-5 were shared by between JBP and STP, JBP and NTP, NTP and STP populations, respectively.whereas HAP-3 was shared by four populations. Among four geographic populations, NTP has only one unique haplotype, STP and TKP each has 6 unique haplotypes and JBP have two unique haplotype. When analyse overall population genetic diversity, overall mean haplotype diversity(h) and overall mean nucleotide diversity were 0.804±0.031 and 0.00149±0.00087,respectively.The genetic distance within and between populations showed that the mean genetic distance between four geographic populations was varied between 0.00137-0.00183;the mean genetic distance between TKP and STP populations was the smallest, while highest genetic distance was between TKP and JBP populations. The genetic distance within populations was 0.00113-0.00170, and the average genetic distance within overall populations was 0.00149±0.00044.In the analysis of genetic differentiation and gene flow between four populations, the FST value ranged from 0.11413 to 0.209179 and the FST value between STP and NTP populations was higher than others. The gene flow between four geographical populations was 0.96-2.02. Among them, the gene flow between between STP and NTP populations was the smallest than othes, too. The genetic differentiation index between each population was consistent with the gene flow results.Phylogenetic analysis showed that both of the NJ tree and ML tree produced the same phylogenetic tree, in this tree all haplotypes were colustered in mosaic,The 19 haplotypes were clustered into 5 lineages, namely, HAP-2, HAP-9, HAP-10 and HAP-11 gathered into Clade A, while HAP-6 and sequences from Genbank JN632644 and AF036282 were composed of Clade B, HAP-1 with HAP-13 and HAP-4 with HAP-14 clustered in Clade C and Clade D, respectively. The other haplotypes were clustered into Clade E.NJ tree and ML tree were in consensus with bayes tree constructed in MrBayes 3.2 software using GTR+G model as a most suitable model for bayes tree.In the demographic histories, Tajima’s D, Fu’s Fs neutrality test statistics and micmach distribution were analyzed by using the Arlequin 3.1 software. Results indicated that the both Tajima’s D and Fu’s Fs of overall Xinjiang population(Tajima’s D=-1.7976, P<0.05; Fu’s FS=-11.9442, P<0.01) were negative on average, and statistically significant. The absolute value of Fu’s Fs was higher than Tajima’s D. To the contrary, to four geographic population, Tajima’s D value in JBP and NTP populations was positive, and Tajima’s D in STP and TKP populations was negative, but not statistically significant. Besides in TKP population, Fu’s Fs values in JBP, NTP and STP were not significant, too. The neutrality test results with mismatch distribution analysis implied that the goitered gazelle populations in Xinjiang once have possibly been experienced population expansion. |
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