Genetic composition, population structure and phylogeography of the loggerhead sea turtle: colonization hypothesis for the Brazilian rookeries

The loggerhead sea turtle, Caretta caretta, is the most common species of sea turtle nesting in Brazil and is listed as endangered by the IUCN. Our study characterizes the genetic structure of loggerheads in Brazil based on mitochondrial DNA control region variability and presents a hypothesis for t...

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Bibliographic Details
Published in:Conservation genetics 2010-06, Vol.11 (4), p.1467-1477
Main Authors: Reis, E. C, Soares, L. S, Vargas, S. M, Santos, F. R, Young, R. J, Bjorndal, K. A, Bolten, A. B, Lôbo-Hajdu, G
Format: Article
Language:English
Subjects:
Animal Genetics and Genomics
Aquatic reptiles
Biodiversity
Biomedical and Life Sciences
Caretta caretta
Colonization
Conservation Biology/Ecology
Conservation genetics
Ecology
Evolutionary Biology
Genetic structure
Genetics
Geography
Haplotypes
Hypothesis testing
Life Sciences
Mitochondrial DNA
Mixed stock analysis
Nesting
phylogeography
Plant Genetics and Genomics
Population structure
Reptiles & amphibians
Research Article
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Summary:The loggerhead sea turtle, Caretta caretta, is the most common species of sea turtle nesting in Brazil and is listed as endangered by the IUCN. Our study characterizes the genetic structure of loggerheads in Brazil based on mitochondrial DNA control region variability and presents a hypothesis for the colonization of Brazilian rookeries. We analyzed 329 samples from Brazilian rookeries and an oceanic foraging ground, and we compared our results with previously published data for other loggerhead populations. Brazilian rookeries had four haplotypes, none of which have been reported for rookeries outside Brazil. Six haplotypes were found in the foraging aggregation. The presence of the CC-A4 haplotype at all sampled sites and the low nucleotide diversity suggest a common origin for all rookeries, with CC-A4 being the ancestral haplotype of the Brazilian populations. The occurrence of three haplotypes in the foraging aggregation that are known only from rookeries outside of Brazil is consistent with the transoceanic migratory behavior of loggerheads. Our results indicated that the colonization of Brazilian rookeries probably occurred from the southern USA stock. This recent colonization most likely followed a north to south route along the Brazilian coastline, influenced by the Brazilian warm current. Our results further suggest the existence of two genetic population units of loggerheads in Brazil and corroborate natal homing behavior in loggerheads.
ISSN:1566-0621
1572-9737
DOI:10.1007/s10592-009-9975-0