Ecological divergence combined with ancient allopatry in lizard populations from a small volcanic island.
Mol Ecol
; 23(19): 4799-812, 2014 10.
Article
em En
| MEDLINE
| ID: mdl-25156032
Population divergence and speciation are often explained by geographical isolation, but may also be possible under high gene flow due to strong ecology-related differences in selection pressures. This study combines coalescent analyses of genetic data (11 microsatellite loci and 1 Kbp of mtDNA) and ecological modelling to examine the relative contributions of isolation and ecology to incipient speciation in the scincid lizard Chalcides sexlineatus within the volcanic island of Gran Canaria. Bayesian multispecies coalescent dating of within-island genetic divergence of northern and southern populations showed correspondence with the timing of volcanic activity in the north of the island 1.5-3.0 Ma ago. Coalescent estimates of demographic changes reveal historical size increases in northern populations, consistent with expansions from a volcanic refuge. Nevertheless, ecological divergence is also supported. First, the two morphs showed non-equivalence of ecological niches and species distribution modelling associated the northern morph with mesic habitat types and the southern morph with xeric habitat types. It seems likely that the colour morphs are associated with different antipredator strategies in the different habitats. Second, coalescent estimation of gene copy migration (based on microsatellites and mtDNA) suggest high rates from northern to southern morphs demonstrating the strength of ecology-mediated selection pressures that maintain the divergent southern morph. Together, these findings underline the complexity of the speciation process by providing evidence for the combined effects of ecological divergence and ancient divergence in allopatry.
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Texto completo:
1
Base de dados:
MEDLINE
Assunto principal:
Especiação Genética
/
Ilhas
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Genética Populacional
/
Lagartos
Tipo de estudo:
Prognostic_studies
Limite:
Animals
País como assunto:
Europa
Idioma:
En
Ano de publicação:
2014
Tipo de documento:
Article