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Abstract Detail



The evolutionary causes and consequences of dioecy across the land plants

Moore, Richard [1], Brown, Jennifer [2], Lappin, Fiona [3], Hawkins, Kevin [4], McDermott, Ross [4].

Genomic conflict and the evolution of plant sex chromosomes.

Sex chromosomes have evolved multiple, independent times as genetic regulators of dioecy in plants. The differential transmission of sexual chromosomes through the female and male lineages, however, can lead to genetic conflict between the sex chromosomes and the evolution of mechanisms that favor the transmission of one sex chromosome over the other; e.g. sex chromosome meiotic drive. Thus, geneic conflict, in addition to sexual selection, can affect the evolutionary trajectory of sex chromosomes in dioecious species. Previously, we found striking differences in the patterns of polymorphism and divergence of four X/Y gene pairs from regions that span the sex-determining region of the young sex chromosomes of Carica papaya; patterns consistent with a signature of sex chromosome meiotic drive. We have expanded our study to include over 20 X/Y gene pairs spanning ~250 kb intervals across the gene enriched regions of the X and Y. We present our analysis of polymorphism and divergence in these loci and show that the X chromosome is defined by large footprints of selective sweeps, while the Y is defined by extended regions of elevated polymorphism punctuated by genes with little or no polymorphism. We suggest that the broad distribution of these patterns across the X and Y, are affected by their unique pericentromeric location and the low recombination rates that characterize this region. Furthermore, we posit that these patterns of polymorphism can be explained by sex chromosome meiotic drive and the cycling of X-linked drivers and Y-restorers in the population.

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1 - Miami University, Botany, 316 Pearson, Oxford, OH, 45056, USA
2 - Miami University, Botany, 78 Kelly Drive, Oxford, OH, 45056, USA
3 - Miami University, Department of Botany, 316 E.High St, Oxford, OH, 45056, USA
4 - Miami University, Botany, 316 Pearson Hall, Oxford, OH, 45056, USA

Keywords:
dioecy
sex chromsomes
Genomics
Sexual Conflict.

Presentation Type: Symposium or Colloquium Presentation
Session: SY05
Location: Jasperwood/Riverside Hilton
Date: Monday, July 29th, 2013
Time: 5:15 PM
Number: SY05008
Abstract ID:575
Candidate for Awards:None


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