Molecular Ecology and Evolution
Sherman, Natasha , Muir, Christopher , Josephs, Emily , Moyle, Leonie .
Population variation for reproductive isolating QTL in Solanum.
The strength of isolation between species can vary greatly depending upon the specific source populations used in interspecific crosses. This is because geographically separated populations that experience different selective forces or stochastic events can fix alternative genetic variants; these, in turn, can have very different pleiotropic consequences for species barriers. Under this scenario, local processes are more important in fixing alleles contributing to species barriers than forces acting throughout the entire species range. Therefore, the dynamics driving the evolution of isolating genes that are fixed (invariant within species) versus polymorphic (intraspecifically varying) are expected to be quite different. To understand the extent and genetic basis of within-species variation in reproductive isolating loci, we simultaneously mapped QTL in two independent populations (Rilpop1 & Rilpop2) of recombinant inbred lines(RILs) generated from two independent crosses between the wild species Solanum pimpinellifolium and the domesticated tomato S. lycopersicum. Parental Solanum pimpinellifolium accessions for each population were from geographically distant (>380km), ecologically differentiated ends of the wild species range. For pollen sterility barriers, we identified three and five QTL in Rilpop1 and Rilpop2, respectively. Only one QTL, on the top of linkage group twelve, was detected in both populations. Our results suggest that intraspecific variation for genetically-based species barriers is extensive. No QTL for seed sterility were identified in either population. To assess whether our pollen sterility QTL are associated with potentially selected differences between S. pimpinellifolium source populations, we are also mapping morphological and physiological QTL in each RIL population, and assessing the degree of association between these loci and our polymorphic sterility QTL.
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1 - Indiana University, Department of Biology, Jordan Hall 325, 1001 E. Third St., Bloomington, IN, 47405-3700, USA
2 - University of Toronto, Department of Ecology & Evolutionary Biology, University of Toronto, 25 Willcocks Street, Toronto, Ontario, M5S3B2, Canada
Presentation Type: Oral Paper:Papers for Topics
Location: Westminster Room/Chase Park Plaza
Date: Monday, July 11th, 2011
Time: 2:00 PM