A.D.F. studies evolutionary processes in marine mammals, principally killer whales, with a particular focus on the interaction between ecology, phenotype and genotype. J.N. studies animal and plant ecology through the use of stable isotope including ontogenetic and geographic variation in marine mammals. S.B.P. is a molecular ecologist with a focus on understanding the causes and consequences of variation in levels of genetic diversity among natural populations. E.W. works in the fields of ancient DNA, DNA degradation, and evolutionary biology, with a particular interest in ancient sedimentary and ice core genetics. M.T.P.G is a molecular biologist with broad scale evolutionary, anthropological and archaeological interests that he studies using both modern and ancient DNA.
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Ecological, morphological and genetic divergence of sympatric North Atlantic killer whale populations
Article first published online: 16 DEC 2009
DOI: 10.1111/j.1365-294X.2009.04407.x
© 2009 Blackwell Publishing Ltd
Additional Information
How to Cite
FOOTE, A. D., NEWTON, J., PIERTNEY, S. B., WILLERSLEV, E. and GILBERT, M. T. P. (2009), Ecological, morphological and genetic divergence of sympatric North Atlantic killer whale populations. Molecular Ecology, 18: 5207–5217. doi: 10.1111/j.1365-294X.2009.04407.x
Publication History
- Issue published online: 16 DEC 2009
- Article first published online: 16 DEC 2009
- Received 12 July 2009; revision received 22 September 2009; accepted 23 September 2009
Keywords:
- Atlantic;
- ecotype;
- killer whale;
- Orcinus orca;
- Phylogenetics
Abstract
Ecological divergence has a central role in speciation and is therefore an important source of biodiversity. Studying the micro-evolutionary processes of ecological diversification at its early stages provides an opportunity for investigating the causative mechanisms and ecological conditions promoting divergence. Here we use morphological traits, nitrogen stable isotope ratios and tooth wear to characterize two disparate types of North Atlantic killer whale. We find a highly specialist type, which reaches up to 8.5 m in length and a generalist type which reaches up to 6.6 m in length. There is a single fixed genetic difference in the mtDNA control region between these types, indicating integrity of groupings and a shallow divergence. Phylogenetic analysis indicates this divergence is independent of similar ecological divergences in the Pacific and Antarctic. Niche-width in the generalist type is more strongly influenced by between-individual variation rather than within-individual variation in the composition of the diet. This first step to divergent specialization on different ecological resources provides a rare example of the ecological conditions at the early stages of adaptive radiation.