| Forest musk deer (Moschus berezovskii), a species belong to genus Moschus of the family Moschidae in the order of Artiodactyla, only distributs throughout the forest and mountainous parts of Asia, and for hundreds of years the musk secreted by the male has been widely used as an important kind of raw material in medical, food and perfume industries. The distribution range and population size of musk deer have been sharply declining in the past decades due to over-hunting for musk and the loss of habitats. Therefore, all species of musk deer have been included in Category I of the State Key Protected Wildlife List in China.To decrease the survival pressure of wild populations, the farming of Forest musk deer was started early in 1950s, but there are still some problems in captive populations. The musk productivity of captive populations tends to decrease gradually generation after generation. Many researchers are curious to know whether it has some connections with the loss of genetic diversity caused by close breeding, but no study about it has been reported so far.In this study, for the first time, we use Amplified Fragment Length Polymorphism (AFLP) as the genetic marker to conduct a general survey on the genetic diversity of the Forest musk deer's captive populations and also on the linkage between the performance of musk productivity and the AFLP markers, with 35 Forest musk deers sampled from two farming populations (21 from Baisha Farm and 14 from Jinfeng Mountain Farm) of Sichuan Musk Deer Breeding Institute. The preliminary results are as follows:(1) To assess the genetic diversity of the Forest musk deer's captive populations, a total of 29 pairs of AFLP primers were used. At population level of average, the percentage of polymorphic loci (PPL) was 98.96%, the effective number of alleles per locus (Ne) was 1.6006, Shannon's information index (i) was 0.5277, and Nei's gene diversity (H) was 0.3531, respectively. The results reveal a high level of genetic diversity of both farming populations, without an evident decline of genetic polymorphism. According to the compare result of PPL and H value, population of Jinfeng Mountain shews a higher level of genetic diversity.(2) Nei's genetic distance (GD) between individuals ranged from 0.011 0 to 0.1004 with an average of 0.0458±0.0165, indicating an even distribution of genetic diversity among individuals. The coefficient of genetic differentiation (Gst) was 0.0273. which means that only 2.73% of the genetic diversity were distributed between the two farming populations. Nei's unbiased measure of genetic distance (DS) and the gene flow (Nm) between the two fanning populations were 0.0108 and 22.9762 respectively, both of which suggest that small differentiation occurs between the two populations and that gene transfer is frequent.(3) To analyse the linkage between the performance of musk productivity and AFLP markers, a total of 41 combinations of primers were detected. The T-test results revealed that the PPL of high productivity group was significantly higher than the male reference group (P<0.01) while the PPL of low productivity group was significantly lower than the male reference group (P<0.01). This suggests that the musk productivity has a positive correlation with the level of genetic diversity. According to the comparative result between high and low groups, ten combinations of selective primers with significantly differences in amplified fragment frequency (P<0.01) were selected. Homogeneity test of 34 AFLP loci showed significant differences in the distributions of amplified bands between high and low groups (P<0.05), and another 17 AFLP loci were screened out from the comparison between male group and female reference group. These selected AFLP primers and loci may relate to the genetic factors that control the performance of musk production, so that they provide some preferred selections of AFLP primers and marked loci for continued study on the search for the QTL of musk production.
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