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Testing the molecular and evolutionary causes of a ‘leapfrog’ pattern of geographical variation in coloration
Author(s) -
CADENA C. D.,
CHEVIRON Z. A.,
FUNK W. C.
Publication year - 2011
Publication title -
journal of evolutionary biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.289
H-Index - 128
eISSN - 1420-9101
pISSN - 1010-061X
DOI - 10.1111/j.1420-9101.2010.02175.x
Subject(s) - biology , evolutionary biology , disjunct , coalescent theory , phylogenetic tree , plumage , genetic drift , genetic algorithm , phylogenetics , phenotypic trait , genetic variation , phenotype , genetics , gene , zoology , population , demography , sociology
Understanding the mechanisms accounting for the evolution of phenotypic diversity is central to evolutionary biology. We use molecular and phenotypic data to test hypotheses for ‘leapfrog’ patterns of geographical variation, in which phenotypically similar, disjunct populations are separated by distinct populations of the same species. Phylogenetic reconstructions revealed independent evolution of melanic plumage characters in different populations in the Neotropical avian genus Arremon . Thus, phenotypic similarities between distant populations cannot be explained by close phylogenetic affinity. Nor can they be attributed to recurring mutations in the MC1R gene, a locus involved in melanic pigmentation. A coalescent analysis indicates that plumage traits have become fixed at a faster rate than expected under genetic drift, suggesting that selection underlies their repeated evolution. In contrast to views that genetic drift drives phenotypic differentiation in Neotropical montane birds, our results imply that geographical variation preceding speciation may reflect the action of deterministic selective processes.