Genetic Analysis of the Galapagos tortoise, Geochelone nigra : taxonomic relationships among subspecies and population assignment of captive individuals /
of Galapagos tortoise, Geochelone nigra, were
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| Format: | Thesis Book |
| Language: | English |
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[Place of publication not identified] :
[publisher not identified] ;
1997.
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| Online Access: | http://proxy.library.tamu.edu/login?url=http://proquest.umi.com/pqdweb?did=733007801&sid=1&Fmt=2&clientId=2945&RQT=309&VName=PQD |
| Summary: | of Galapagos tortoise, Geochelone nigra, were investigated utilizing microsatellite nuclear DNA analysis and mitochondrion DNA sequence data. From these molecular techniques, eleven extant subspecies (Pinta Island (G. n. abingdoni ), VolcØn Wolf (G n. becki), San Cristb̤al (G n. chathamensis ), Santiago (G. n. darking ), Pinzn̤ (G. n. ephippium ), Espahola (G. n. hoodensis ), VolcØn Darwin (G. n. microphyes ), Santa Cruz (G. n. nitrite ), VolcØn Alcedo (G. n. vandenburghi ), Southern Isabela (G n. vicuna ) and Northwest Santa Cruz (G nigra ssp.l) were resolved. Four extinct subspecies ((Floreana (G n. galapagoensis ), Santa Fł (G. nigra ssp.), Fernandina (G n. phantasticus ), and (G. n. walleyed )) 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 Southern 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 a priori assumptions of equal probability of subspecific assignment to any 01 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-locus 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. |
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| Item Description: | Vita. "Major Subject: Genetics". |
| Physical Description: | xiv, 207 leaves : illustrations ; 28 cm. Issued also on microfiche from University Microfilm Inc. |
| Bibliography: | Includes bibliographical references (leaves 117-140). |