Current address: Center for Tropical Research, Institute of the Environment, University of California, Los Angeles, California 90095.
MIGRATION-SELECTION BALANCE AND LOCAL ADAPTATION OF MITOCHONDRIAL HAPLOTYPES IN RUFOUS-COLLARED SPARROWS (ZONOTRICHIA CAPENSIS) ALONG AN ELEVATIONAL GRADIENT
Version of Record online: 2 FEB 2009
© 2009 The Author(s). Journal compilation © 2009 The Society for the Study of Evolution
Volume 63, Issue 6, pages 1593–1605, June 2009
How to Cite
Cheviron, Z. A. and Brumfield, R. T. (2009), MIGRATION-SELECTION BALANCE AND LOCAL ADAPTATION OF MITOCHONDRIAL HAPLOTYPES IN RUFOUS-COLLARED SPARROWS (ZONOTRICHIA CAPENSIS) ALONG AN ELEVATIONAL GRADIENT. Evolution, 63: 1593–1605. doi: 10.1111/j.1558-5646.2009.00644.x
- Issue online: 21 MAY 2009
- Version of Record online: 2 FEB 2009
- Received October 1, 2008Accepted December 31, 2008
- cline analyses;
- ecological speciation;
- environmental gradients;
- gene flow;
- natural selection
Variable selection pressures across heterogeneous landscapes can lead to local adaptation of populations. The extent of local adaptation depends on the interplay between natural selection and gene flow, but the nature of this relationship is complex. Gene flow can constrain local adaptation by eroding differentiation driven by natural selection, or local adaptation can itself constrain gene flow through selection against maladapted immigrants. Here we test for evidence that natural selection constrains gene flow among populations of a widespread passerine bird (Zonotrichia capensis) that are distributed along an elevational gradient in the Peruvian Andes. Using multilocus sequences and microsatellites screened in 142 individuals collected along a series of replicate transects, we found that mitochondrial gene flow was significantly reduced along elevational transects relative to latitudinal control transects. Nuclear gene flow, however, was not similarly reduced. Clines in mitochondrial haplotype frequency were strongly associated with transitions in environmental variables along the elevational transects, but this association was not observed for the nuclear markers. These results suggest that natural selection constrains mitochondrial gene flow along elevational gradients and that the mitonuclear discrepancy may be due to local adaptation of mitochondrial haplotypes.