Preliminary Study On The Genetic Diversity And Population Genetic Structure Of Chinese Crocodile Lizard(shinisaurus Crocodilurus)

Chinese crocodile lizard(Shinisaurus crocodilurus)is a National Class I protected animal in China. Studies on the biology of Chinese crocodile lizard are helpful to gain insight into the origin and evolution of reptiles, but the population of it declined rapidly in recent years and it is at the brink of extinction. Study on its genetic diversity and genetic structure is important to reveal the status of its genetic diversity and make protection measures. In this thesis, we used mitochondrial DNA(mtDNA) control region sequences as a molecular marker to study the genetic diversity and population genetic structure of five geographical populations of Chinese crocodile lizard, including the population of Zhaoping, Datengxia, Daguishan, Luoxiang and Luokeng Nature Reserve. We got following conclusions:(1) Genetic diversity of Chinese crocodile lizard in our country is relative high (π= 0.02913±0.03453, h = 0.990±0.008). Among the five geographical populations, Zhaoping population has the highest genetic diversity (π= 0.03963±0.03832), Luokeng populations has the lowest genetic diversity (π=0.00180±0.00680).(2) There has genetic differentiation on some degree among the five geographical populations. Both the genetic differentiation of Luokeng population and Datengxia population are significant. Genetic variation between geographical populations (53.61%) is higher than that in the geographic populations (46.39%).(3) Population expansion occurred in the evolutionary history of Chinese crocodile lizard population.(4) The haplotype diversity of Chinese crocodile lizard populations is high, however the nucleotide diversity of it is low.(5) The endangered state of Chinese crocodile lizard is not caused by low genetic diversity.Based on above results, combined with the habitat background of and population dynamics of Chinese crocodile lizard, following protecting measures were recommended.(1) Habitat and population fragmentation trends of Chinese crocodile lizard should be controlled. Poaching and other threaten activities should be forbidden. Effective measures should be made to decrease the decline of the population and the loss of genetic diversity of Chinese crocodile lizard.(2) Since the genetic differentiation among the five geographical populations is significant, the five geographical populations should be protected as five management unit respectively.(3) Although the genetic diversity of Luokeng populations is the lowest among the 5 geographical populations, the population in Luokeng Nature Reserve is the largest. In order to protect the gene pool, the population in Luokeng should get priority of protection.(4) In order to keep insight into the biology of this species further, we should strengthen the combination study of molecular ecology and macro-ecology of Chinese crocodile lizard.