Scascitelli, Moira , Randell, Rebecca A , Whitney, Kenneth D , Buerkle, Alex , Rieseberg, Loren H. .
Genome-wide analysis of the effects of inter-specific gene flow in annual sunflowers.
The common sunflower Helianthus annuus is known to have spread outside the original range of distribution and to have hybridized with other Helianthus species. In some instances the resulting hybrids gave rise to new species through a process of "homoploid hybrid speciation". In Texas, hybridization between H. annuus and a local endemic H. debilis is thought to have formed a new stable race: H. annuus ssp. texanus. Interestingly, these sunflowers have gained several morphological traits similar to H. debilis, suggesting the possibility that adaptation to Texas habitats was facilitated by the introgression of adaptive traits from H. debilis to H. annuus texanus. Here, we examine the population structure and genetic composition in Texas and non-Texas sunflowers, by analyzing 90 microsatellites developed from Expressed sequence Tags (ESTs).
All the populations from Texas analyzed exhibited extensive interspecific gene flow. As predicted, individuals from H. annuus texanus do appear to contain genetic material from H. debilis. However, we also see introgression into H. debilis and into typical populations of H. annuus. Most markers follow patterns of introgression consistent with neutral expectations rather than adaptive introgression. Finer-scale analyses may be required to identify the latter.
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1 - University of British Columbia, Botany Department, 3529-6270 University Boulevard, Vancouver, British Columbia, V6T 1Z4, Canada
2 - Indiana University, Department of Biology, Jordan Hall, 1001 East Third Street, Bloomington, Indiana, 47405, USA
3 - Rice University, Ecology and Evolutionary Biology, 6100 Main St., MS 170, Houston, Texas, 77005, USA
4 - University of Wyoming, Department of Botany, 3165, 1000 E University Avenue, Laramie, Wyoming, 82071, USA
5 - University of British Columbia, Department of Botany, 3529-6270 University Blvd, Vancouver, BC, V6T 1Z4, Canada
Presentation Type: Poster:Posters for Topics
Location: Ball Room & Party Room/SUB
Date: Monday, July 28th, 2008
Time: 12:30 PM