Present address: Department of Biology, 1009 Main Building, 100 Washington Square East, New York University, New York, NY 10003-6688, USA.
Diversity and divergence patterns in regulatory genes suggest differential gene flow in recently derived species of the Hawaiian silversword alliance adaptive radiation (Asteraceae)
Article first published online: 3 SEP 2007
Volume 16, Issue 19, pages 3995–4013, October 2007
How to Cite
LAWTON-RAUH, A., ROBICHAUX, R. H. and PURUGGANAN, M. D. (2007), Diversity and divergence patterns in regulatory genes suggest differential gene flow in recently derived species of the Hawaiian silversword alliance adaptive radiation (Asteraceae). Molecular Ecology, 16: 3995–4013. doi: 10.1111/j.1365-294X.2007.03445.x
- Issue published online: 3 SEP 2007
- Article first published online: 3 SEP 2007
- Received 19 November 2006; revision accepted 4 June 2007
- adaptive radiation;
- gene flow;
- Hawaiian silversword alliance;
- regulatory gene evolution;
The impact of gene flow and population size fluctuations in shaping genetic variation during adaptive radiation, at both the genome-wide and gene-specific levels, is very poorly understood. To examine how historical population size and gene flow patterns within and between loci have influenced lineage divergence in the Hawaiian silversword alliance, we have investigated the nucleotide sequence diversity and divergence patterns of four floral regulatory genes (ASAP1-A, ASAP1-B, ASAP3-A, ASAP3-B) and a structural gene (ASCAB9). Levels and patterns of molecular divergence across these five nuclear loci were estimated between two recently derived species (Dubautia ciliolata and Dubautia arborea) which are presumed to be sibling species. This multilocus analysis of genetic variation, haplotype divergence and historical demography indicates that population expansion and differential gene flow occurred subsequent to the divergence of these two lineages. Moreover, contrasting patterns of allele- sharing for regulatory loci vs. a structural locus between these two sibling species indicate alternative histories of genetic variation and partitioning among loci where alleles of the floral regulatory loci are shared primarily from D. arborea to D. ciliolata and alleles of the structural locus are shared in both directions. Taken together, these results suggest that adaptively radiating species can exhibit contrasting allele migration rates among loci such that allele movement at specific loci may supersede genetic divergence caused by drift and that lineage divergence during adaptive radiation can be associated with population expansion.