Harkess, Alex , Weingartner, Laura , Moore, Richard .
Divergent haplotype structure on the Carica papaya Y chromosome.
The male specific region of the Y (MSY) chromosome in Carica papaya is estimated to have diverged from the corresponding X region approximately 2 mya. Consistent with this relatively recent divergence, suppression of recombination between the X and the MSY is confined to an approximately 8 Mbp region that spans the centromere of chromosome 1, comprising about 10% of the chromosome length. We analyzed patterns of polymorphism and divergence for six gene pairs that span the MSY region and found evidence of elevated polymorphism on the Y chromosome. This is an unexpected pattern of diversity, as examples of young sex chromosomes from other plant and animal species exhibit reduced patterns of polymorphism. We developed haplotype networks for the MSY genes and compared them to those for homologous X regions and autosomal loci. We found evidence of three distinct haplotypes associated with MSY loci, but not found in X and autosomal loci. We characterized the distribution of haplotypes across regions of Costa Rica and among cultivars and found significant heterogeneity in this pattern. These haplotypes extend across the MSY as evidenced by significant levels of linkage disequilibrium. We hypothesize that these haplotypes are the result of MSY-specific population structure due perhaps to limited pollen flow among geographic regions.
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1 - Miami University, Botany, 316 Pearson Hall, Oxford, OH, 45056, USA
2 - Indiana University, Jordan Hall, 1001 E Third St., Bloomington, IN, 47405, USA
Presentation Type: Poster:Posters for Topics
Location: Khorassan Ballroom/Chase Park Plaza
Date: Monday, July 11th, 2011
Time: 5:30 PM