Molecular Ecology and Evolution
Hill, Elizabeth , Church, Sheri A. .
Identifying speciation genes in wild sunflower (Helianthus) species.
Understanding the process of speciation remains a fundamental question in evolutionary biology. In particular, understanding the genetic basis of species divergence remains difficult. Many wild species of Helianthus are ecologically quite divergent. Even closely related species exist in drastically different habitats. The genes that are involved in these unique adaptive differences would likely be under positive selection, meaning that mutations have offered fitness advantages and subsequently been selected for. The signature of such selection would be evident in the sequences of these genes and be seen as a higher rate of substitution of nonsynonymous mutations relative to synonymous mutations. Thus, by comparing rates of nonsynonymous to synonymous substitutions, we can identify genes that are under positive selection.
Previous studies have identified candidate speciation genes in several closely related sunflower (Helianthus) species. The current study expanded this research to examine the evolutionary fate of these candidate genes in 13 other wild sunflower species. The results suggest that selection varies across species in regard to these genes. In particular, three genes were found to be under positive selection across several lineages whereas 8 other genes showed species specific evidence of positive selection. The results of this study suggest that some genes may be responsible for similar adaptations across a variety of taxa. In other cases, unique mutations may be driving species divergence in sunflowers.
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1 - George Washington University, Biological Sciences, 2023 G St. NW, 340 Lisner Hall, Washington, DC, 20052, USA
2 - George Washington University, Department of Biological Sciences, Lisner Hall 340, 2023 G Street, NW, Washington, DC, 20052, USA
Presentation Type: Poster:Posters for Topics
Location: Exhibit Hall (Northeast, Southwest & Southeast)/Hilton
Date: Sunday, July 8th, 2007
Time: 8:00 AM