Filogeografia de golfinhos rotadores (Stenella longirostris Gray, 1828) no litoral brasileiro a partir de marcadores mitocondriais
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Data
2012-02-28
Autores
Volpi, Thaís de Assis
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Universidade Federal do Espírito Santo
Resumo
The pantropical spinner dolphin (Stenella longirostris longirostris) occurs in tropical and subtropical waters of all oceans. In the Brazilian coast, it occurs mainly in tropical waters between 170 and 2700m depth, being very common in Fernando de Noronha Archipelago. Little is known about its gene flow and genetic diversity in South Atlantic Ocean. The present study aimed to evaluate the genetic variability of spinner dolphin in different localities of the Brazilian coast. Two regions of the mitochondrial DNA were analyzed, control region (D-loop) and cytochrome Oxidase subunit I (COI). 82 individuals were sampled, corresponding to four putative groups of dolphins sampled in Northeast Brazil (G1), in Fernando de Noronha (G2 and G3) and in the Southeast and South of Brazil (G4). The samples were obtained by skin swabbing, skin biopsy, and dead animals found stranded. 79 sequences with 414bp for D-loop and 48 with 714bp for COI region were analyzed. In addition to these, 45 sequences were generated from the link between fragments of D-loop and COI. 115 GenBank sequences (109 of D-loop and six of COI) were included to understand the relationship of Brazilian haplotypes with other world populations. The four Brazilian groups evaluated showed significant intergroup genetic differentiation (Fst>0.05 with P<0.05), therefore, each one of them was considered to be a different population. G4 presented the highest nucleotide and haplotypic diversity indices, while G2 and G3 showed the lowest. The low gene flow between the spinner dolphin populations from Fernando de Noronha in relation to the non insular populations may indicate site fidelity of these animals to insular waters. The populations in the Brazilian coast are genetically distinct; however all share haplotypes with dolphins from Indian and Pacific oceans, in addition to animals of the northern portion of the Atlantic. G4 showed more genetic similarity with dolphins from other oceans than with other spinner dolphin Brazilian populations. The population G2 (with the highest number of samples) showed greater genetic similarity with the Pacific population, even when compared with another population of Fernando de Noronha (G3). Thus, it is possible that the gene flow of spinner dolphins in Brazil is not given by the geographical distance among them, but by other historical, ecological and behavioral factors.
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Palavras-chave
Cetacean , Genetic diversity , Gene flow , Population structure , Diversidade genética , Fluxo gênico , Estrutura populacional
Citação
VOLPI, Thaís de Assis. Filogeografia de golfinhos rotadores (Stenella longirostris Gray, 1828) no litoral brasileiro a partir de marcadores mitocondriais. 2012. 112 f. Dissertação (Mestrado em Biodiversidade Tropical) - Universidade Federal do Espírito Santo, Centro Universitário Norte do Espírito Santo, São Mateus, 2012.