Lawton-Rauh, Amy , Purugganan, Michael , Robichaux, Robert H. .
Diversity and divergence patterns in regulatory genes
suggest differential gene flow in recently-derived species of the Hawaiian
silversword alliance adaptive radiation (Heliantheae, Asteraceae).
The impact of gene flow on genetic variation during adaptive radiation, at both the genome-wide and gene-specific levels, is very poorly understood. To examine the relationship between gene flow patterns among adaptively radiating species and lineage divergence in the Hawaiian silversword alliance adaptive radiation, we investigated the nucleotide sequence diversity and divergence patterns of several floral regulatory genes and a structural/housekeeping gene. Patterns of variance and divergence across these five loci were estimated between two recently-derived species presumed to be sibling species as well as among populations within each species. Our multi-locus analyses of genetic variation, haplotype divergence and historical demography indicate that population expansion and differential gene flow occurred subsequent to the divergence of these two lineages. Moreover, patterns of allele sharing at regulatory loci are different than patterns in the structural/housekeeping locus examined between species, indicating alternative histories of genetic variation and partitioning among loci. Allele partitioning patterns further suggest that alleles of the floral regulatory loci are shared primarily in one direction and alleles of the structural/housekeeping locus are shared in both directions with variance patterns similar to other random markers. Taken together, our results suggest that adaptively radiating species can exhibit contrasting allele migration rates among loci between recently-derived species that may be sufficient to supersede genetic divergence caused by drift. These results as well as a proposed model associated with life history evolution in the Hawaiian silversword alliance will be presented.
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Lawton-Rauh Lab website
1 - Clemson University, Genetics & Biochemistry, 101 Jordan Hall, Clemson, South Carolina, 29634-0318, USA
2 - New York University, Department of Biology/Center for Comparative Functional Genomics, 1009 Silver, 100 Washington Square East, New York, New York, 10003, USA
3 - University of Arizona, Department of Ecology and Evolutionary Biology, P.O. Box 210088, Tucson, Arizona, 85721, USA
Hawaiian silversword alliance
MADs box genes.
Presentation Type: Oral Paper:Papers for Topics
Location: Williford A/Hilton
Date: Tuesday, July 10th, 2007
Time: 10:30 AM