Literaturdatenbank
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Louis, E. E. (1997). Genetic analysis of the galapagos tortoise, geochelone nigra: taxonomic relationships among subspecies and population assignment of captive individuals. Unpublished thesis , A&M University.
Added by: Sarina Wunderlich (25 Jan 2011 10:32:05 UTC) |
| Resource type: Thesis/Dissertation BibTeX citation key: Louis1997 View all bibliographic details  |
Categories: General Keywords: Chelonoidis, Chelonoidis nigra, Genetik = genetics, Schildkröten = turtles + tortoises, Systematik = taxonomy, Testudinidae Creators: Louis Publisher: A&M University |
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| Abstract |
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Testudinidae The phylogenetic relationships among the populations of Galapagos tortoise, Geochelone nigra, were investigated utilizing microsatellite nuclear DNA analysis and mitochondrial DNA sequence data. From these molecular techniques. eleven extant subspecies (Pinta Island (G. n. abingdoni), VoIcan Wolf (G. n. becki), San Crist6bal (G. n. chathamensis ), Santiago (G. n. danvini ), Pinz6n (G. n. ephippium ), Espai'iola (G. n. hoodensis ), VoIcan Darwin (G. n. microplzyes ), Santa Cruz (G. n. nigrita ), VoIcan AIcedo (G. n. vandenburghi ), Southem Isabela (G. n. vicina ) and Northwest Santa Cruz (G. nigra ssp.» were resolved. Four extinct subspecies (Floreana (G. n. galapagoensis ), Santa Fe (G. nigra ssp.), Femandina (G. n. phantasticus ), and (G. n. wallecei » remain unresolved. Although neighbor-joining analysis of the microsatellite nuclear DNA data provided strong support for the differentiation of a majority of the island races, genetic distances between the subpopulations of Southem Isabela were so small that these populations were consolidated as a metapopulation. Utilizing a maximum likelihood estimation approach, a model was designed to determine the posterior probability of a captive tortoise belonging to one of the ten representative populations. The model combined the allele frequencies observed in each of the ten populations with the apriori assumptions of equal probability of subspecific assignment to any of these populations. Hardy-Weinberg genotype proportions and gametic phase equilibrium among loci. By incorporating a Bayesian approach. the algorithm generated the relative likelihood that the multi-Iocus genotype scored for an individual tortoise with no known locality data originated from each of the ten populations. Utilizing this algorithm. one hundred and twenty captive tortoises have been assigned to a specific population.
Added by: Sarina Wunderlich |