The Individual Dispersal Mechanism Of Blue Sheep Based On Molecular Biology

Dispersal is a single linear movement away from each other between individuals and also is a biological characteristic of organism; it has important influence in the distribution, dynamic and genetic structure of population. Dispersal has great significance to species population dynamics and population development especially when densities of individuals are increasing, food and live resources are insufficient. Blue sheep (Pseudois nayaur) is endemic to Tibetan Plateau, and is listed in the second gmde nationally protected animals of China. We choose Helan Mountain nature reserve as our study area where located in Ningxia province. The Helan Mountain Region is surrounded by Yinchuan City, deserts, and Yellow River. Consequently, the blue sheep population of the Helan Mountain is a special edge population. And the blue sheep population has a large increase in Helan Mountian region for the twenties years. So in this case, find out how blue sheep populations disperse has great importance to the protection and management of the species. We study the individual dispersal mechanism of blue sheep in the south of Helan Mountain with the technology based on the molecular and macroscopic analysis, the results are as follows:1. Screening fecal microsatellite DNA markersWe screening 10 microsatellite primers can steady amplification in the fecal sample of blue sheep,9 for this research to identify blue sheep individual (except BOYILS52). The size of microsatellite loci in this research are between 100 bp to 200 bp (range of microsatellite size), and are with high polymorphism. This indicated that these loci are differences between individuals and are suitable for the reaearch of genetic diversity and individual identification of blue sheep. We identify 183 blue sheep individuals from 222 fecal samples of extract successly by using the 9 loci.2. Analysis of genetic diversityStatistical results shows that we detected a total of 49 alleles with 9 microsatellite loci. The number of alleles is from 3 (BL42) to 9 (BMS2461), the average is 5.44. Genetic heterozygosis are between 0.26-0.95, the average heterozygosity is 0.48, higher than endangered species or hoofed animals after building group and bottleneck; Polymorphism is between 0.23-0.68, with an average of 0.48, so microsatellite polymorphism of blue sheep in study area is not poor, but at an intermediate level.3. Sex identification and parentage analysisWe identify the sex of the blue sheep using the amelogenin gene, according to the results of sex identification,183 individuals include 93 female individuals and 90 male individuals, sex ratio is 93:90 (1.03:1), this conform to the sex composition of blue sheep in Helan Mountain. We have identified 17 group individuals have the Parentage relationship, and found no identified offspring as the parents continue to breed, we make an assumption here that it is possible that previous individuals disperse around are disperse further after sexual maturation.4. The sub-population and the sex ratioWe divide the blue sheep individuals into four sub-populations in our research area, and analyze the difference of each sub-population in the habitat factors. We found that all factors have significant difference except food richness and human disturbance, we also found that habitat factors of B sub-population with high differences with three other sub-populations. Where D sub-populations area mostly are male, and the habitat factor of D is same as other reported about males habitat requirements. Sex ratio of blue sheep individuals in four sub-populations are as follows respectively:A. a total of 33 individuals, sex ratio is 25:8 (3.13:1); B. a total of 48 individuals, sex ratio is 24:24 (1:1); C. a total of 46 individuals, sex ratio is 24:22 (1.09:1); D. a total of 56 individuals, sex ratio is 20:36(0.56:1). We can know the individuals in A sub-population are female predominantly, the female has not been found as the parent appeared in the parentage relationship, we assume that these female are fail in reproduction and stay in the cluster area waiting for next breeding season. D sub-population individuals are primary males,10 of 17 male parents are from D sub-population in parentage relationship identification, and this indicate that the area of D sub-population is the main area of male population gather in the breeding season.5. The dispersal analysisThe result shows that there are communication of individuals among the four sub-populations, and both the male and female individuals disperse from the mother population, that is to say, there is no sex biased dispersal in blue sheep in our research. It is also illustrates that maybe the factor leads the dispersal of blue sheep individuals are food resources or population density because both the male and female individuals disperse from the mother population. We also found that male and female individuals have moved in male parent sub-population, if the female individuals without further migration, this may indicate that inbreeding is not main cause of the dispersal, blue sheep may have some sort of recognition mechanism between individuals; If the female individual move out when they are in sexual maturation, it shows that the pressure of survival resources and inbreeding avoided contributed to the dispersal of blue sheep individual together. In addition, different preferences of male and female individual on habitat selection will determine the habitats they move to are different.