| The Hooded Crane (Grits monacha) is a large migratory wading bird; there are about10160individuals worldwide. It is designated as a Vulnerable species in IUCN Red List and First-class National Protected Wild Animal species in China. During the past two decades, due to habitat loss, hunting, pollution, pesticides and human activities, the population size has undergone continuous decline. In this study, using feces as sources of DNA samples, we analyzed the mtDNA D-loop sequences based genetic diversity of Hooded Crane populations wintering in the wetlands in the middle and lower reaches of the Yangtze River. We screened the polymorphic microsatellite loci of Hooded Cranes through cross-amplification PCR to analysis the genetic diversity, so as to accumulate the genetic basic data for this threatened species.1. The full-length of72(34came from this study and38in the past) D-loop sequences of the four Hooded Crane wintering populations in the middle and lower reaches of Yangtze River ranged from1103bp to1104bp, containing26variable sites (2.4%), including8parsimony-informative sites,16singleton sites,1deleted site and an inserted site. The average contents of A, G, C and T bases were30.48%,14.77%,25.55%and29.20%respectively; the content of A+T (59.68%) was higher than that of G+C (40.32%).2. The average haplotype diversity and nucleotide diversity of mitochondrial control region for the four wintering populations of Hooded Cranes in the middle and lower reaches of Yangtze River, were h=0.823±0.042and π=0.00157±0.00021respectively. Compared with other cranes, this species was lower genetic diversity. And the result of high haplotype diversity and low nucleotide diversity implied that it may be in a rapidly increasing period from a small effective population.3. Tajima’s D and Fu’s Fs tests of mitochondrial control region sequences were all significantly negative (D=-2.10951, P<0.05; Fs=-19.351, P<0.01); and the mismatch distribution of the Chinese population appeared to be a unimodal shape, P-values of SSD and Harpending’s Raggedness index were both over0.05. These results showed that the population has experienced population expansions. According to t=τ/2μk (τ=1.676), we estimated the time since population expansion was about8900-38000years ago.4. According to the NJ tree and network diagram of haplotypes of mitochondrial control region, as well as the analysis results of population difference (FST), gene flow (Nm), and AMOVA of the genetic structure of the populations, we could know that there are close relations among different wintering crane populations, without significant genetic differentiation in the middle and lower reaches of Yangtze River. The results of FST and AMOVA suggested that there may be a certain degree of genetic differentiation between the wintering populations in China and in Japan.5. Seven microsatellite loci were screened through cross-amplifications from closely related species. Together with3microsatellite loci isolated in Hooded Crane itself, a total number of10microsatellite loci were obtained.34alleles were found in8individuals from the Shengjin Lake population.6. The observed heterozygosises (Ho) of10loci ranged from0.375to1, the expected heterozygosises (He) ranged from0.325to0.8, and the Polymorphism Information Content (PIC) ranged from0.258to0.712. The unbiased heterozygosis, average observed heterozygosis, and average number of alleles in SJ population of Hooded Cranes were0.6347±0.0498,0.8196±0.0435and3.40±1.35respectively. Compared with other threatened birds, the level of genetic diversity on microsatellite loci was low. The result is similar to the genetic diversity on mtDNA control region. |
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