Microevolution in island forms: the roles of drift and directional selection in morphological divergence of a passerine bird

Clegg, S. M., Degnan, S. M., Moritz, C. C., Estoup, A., Kikkawa, J. and Owens, I. P. (2002) Microevolution in island forms: the roles of drift and directional selection in morphological divergence of a passerine bird. Evolution, 56 10: 2090-2099. doi:10.1111/j.0014-3820.2002.tb00134.x


Author Clegg, S. M.
Degnan, S. M.
Moritz, C. C.
Estoup, A.
Kikkawa, J.
Owens, I. P.
Title Microevolution in island forms: the roles of drift and directional selection in morphological divergence of a passerine bird
Journal name Evolution   Check publisher's open access policy
ISSN 0014-3820
Publication date 2002-01-01
Sub-type Article (original research)
DOI 10.1111/j.0014-3820.2002.tb00134.x
Volume 56
Issue 10
Start page 2090
End page 2099
Total pages 10
Place of publication Lawrence, KS, USA
Publisher The Society for the Study of Evolution
Language eng
Subject C1
270799 Ecology and Evolution not elsewhere classified
779999 Other
Abstract Theory predicts that in small isolated populations random genetic drift can lead to phenotypic divergence; however this prediction has rarely been tested quantitatively in natural populations. Here we utilize natural repeated island colonization events by members of the avian species complex, Zosterops lateralis, to assess whether or not genetic drift alone is an adequate explanation for the observed patterns of microevolutionary divergence in morphology. Morphological and molecular genetic characteristics of island and mainland populations are compared to test three predictions of drift theory: (1) that the pattern of morphological change is idiosyncratic to each island; (2) that there is concordance between morphological and neutral genetic shifts across island populations; and (3) for populations whose time of colonization is known, that the rate of morphological change is sufficiently slow to be accounted for solely by genetic drift. Our results are not consistent with these predictions. First, the direction of size shifts was consistently towards larger size, suggesting the action of a nonrandom process. Second, patterns of morphological divergence among recently colonized populations showed little concordance with divergence in neutral genetic characters. Third, rate tests of morphological change showed that effective population sizes were not small enough for random processes alone to account for the magnitude of microevolutionary change. Altogether, these three lines of evidence suggest that drift alone is not an adequate explanation of morphological differentiation in recently colonized island Zosterops and therefore we suggest that the observed microevolutionary changes are largely a result of directional natural selection.
Keyword Ecology
Evolutionary Biology
Genetics & Heredity
Genetic Drift
Islands
Microsatellites
Morphology
Selection
Zosterops
Body Size
Phenotypic Evolution
Natural-populations
Speciation
Mutation
Rule
Mammals
Model
Q-Index Code C1

Document type: Journal Article
Sub-type: Article (original research)
Collections: Excellence in Research Australia (ERA) - Collection
School of Biological Sciences Publications
 
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Created: Wed, 15 Aug 2007, 03:25:58 EST