Zhang, Wenyun , Moore, Richard C. .
The evolution of papaya sex chromosomes.
Suppression of X and Y recombination followed by degeneration of the Y chromosome is regarded as the common mechanism for sex chromosome evolution shared by diverse organisms. The sex chromosomes of papaya have recently evolved and have a relative small region of suppressed recombination-the MSY (male specific Y). We were interested in determining the evolutionary forces driving the divergence of the papaya sex chromosomes and the degeneration of the Y chromosome. By performing population genetic analyses of MSY sequences, we expect to find decreased variation in the MSY region relative to X homologous loci, reflective of a decreased effective population size (Ne). We will use the HKA test of selection to determine whether the decreased Ne is due to natural selection. If selection is acting on the MSY, we will use Tajima’s D test statistic to assess the pattern of polymorphism and distinguish the action of a selective sweep or background selection. If we find an excess of rare polymorphism, we can conclude that a selective sweep reduced the diversity of MSY. Otherwise, background selection may drive the Y chromosome degeneration. Through analyzing the genomic organization of the papaya chromosome, we will be able to observe the early events in the sex chromosome evolution.
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1 - Miami University, Botany
Presentation Type: Plant Biology Abstract
Location: Exhibit Hall (Northeast, Southwest & Southeast)/Hilton
Date: Sunday, July 8th, 2007
Time: 8:00 AM