Microsatellite analysis of genetic diversity in the Chinese alligator (Alligator sinensis) Changxing captive population
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Chinese alligator (Alligator sinensis) is a critically endangered species endemic to China. In this study, the extent of genetic variation in the captive alligators of the Changxing Reserve Center was investigated using microsatellite markers derived from American alligators. Out of 22 loci employed, 21 were successfully amplified in the Chinese alligator. Sequence analysis showed loci in American alligators had a bigger average size than that of the Chinese alligators and the longest allele of an individual locus almost always existed in the species with longer stretch of repeat units. Eight of the 22 loci were found to be polymorphic with a total of 26 alleles present among 32 animals scored, yielding an average of 3.25 alleles per polymorphic locus. The expected heterozygosity (H E) ranged at a moderate level from 0.4385 to 0.7163 in this population. Compared to that in the American alligators, a lower level of microsatellite diversity existed in the Changxing population as revealed by about 46% fewer alleles per locus and smaller H E at the homologous loci. The average exclusion power and the ability to detect shared genotypes and multiple paternity were evaluated for those markers. Results suggested that when the polymorphic loci were combined, they could be sensitive markers in genetic diversity study and relatedness inference within the Chinese alligator populations. The level of genetic diversity present in the current Changxing population indicated an important resource to complement reintroductions based on the individuals from the other population. In addition, the microsatellite markers and their associated diversity characterized in this population could be utilized to further investigate the genetic status of this species.
KeywordsAlligator mississippiensis ascertainment bias heterozygosity microsatellite evolution relatedness
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We thank the Changxing Nature Reserve and Breeding Research Center for providing all the Chinese alligator samples used in this study. We are also indebted to the people who helped in the sample collection: they are Changjun Zeng and Yunfei Hao. Thanks also go to Dr. Qiuhong Wan for valuable discussions of the manuscript. This work was supported in part by a grant from the Department of Wildlife Conservation, State Forestry Administration of P.R. of China.
- Chen B, Hua Z, Li B (1985) Chinese Alligator. Anhui Science and Technology Press, Hefei, Anhui, China (in Chinese).Google Scholar
- Chen BH (1990) The past and present situation of the Chinese alligator. Asiat. Herpetol. Res., 3, 129–136.Google Scholar
- Davis LM, Glenn TC, Elsey RM, Brisbin Jr IL, Rhodes WE, Dessauer HC, Sawyer RH (2001a) Genetic structure of six populations of American alligators: a microsatellite analysis. In: Crocodilian Biology and Evolution (eds. Grigg GC, Seebacher F, Franklin CE), pp. 38–50. Surrey Beatty and Sons, Chipping NortonGoogle Scholar
- Huang Z (1981) The Chinese alligator. Oryx, 16, 139–140.Google Scholar
- Jarne P, Lagoda PJL (1996) Microsatellites, from molecules to populations and back. Tree 11, 424–429.Google Scholar
- Raymond M, Rousset F (1995) GENEPOP (Version 1.2): Population genetics software for exact tests and ecumenicism. J. Hered. 86: 248–249Google Scholar
- Sambrook J, Fritsh EF, Maniatis T (1989) Molecular Cloning: A Laboratory Manual, 2nd edn. Cold Spring Harbor Laboratory Press, New YorkGoogle Scholar
- Schweder MEE, Shatters Jr RG, West SH, Smith RL (1995) Effect of transition interval between melting and annealing temperature on RAPD analyses. Biotechniques 38: 40–42Google Scholar
- Zhou YJ (1997) Analysis of the decline of the wild Alligator sinensis population. Sichuan J. Zool. 16: 137 (in Chinese).Google Scholar