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SUMMARY:Epigenetic remodeling of meiotic crossover frequency in Arabidopsi
 s DNA methyltransferase mutants - Natasha Elina\, Epigenetics
DTSTART:20120203T130000Z
DTEND:20120203T133000Z
UID:TALK35542@talks.cam.ac.uk
CONTACT:24938
DESCRIPTION:Meiosis is a reductional division that produces gametes in sex
 ually reproducing eukaryotes. During meiosis homologous chromosomes underg
 o reciprocal genetic exchange\, known as crossover. As this process alters
  patterns of natural genetic variation it has evolutionary importance\, in
  addition to serving as a tool for plant breeding. Crossover frequency is 
 unevenly distributed along chromosomes. For example\, gene-rich euchromati
 c regions undergo more crossovers than the repetitive heterochromatin clos
 e to the centromere. Heterochromatin is maintained by DNA methylation and 
 is dramatically reduced in met1 DNA methyltransferase mutants. We have obs
 erved a extensive remodeling of crossover frequency in met1\, including el
 evated centromeric\, decreased pericentromeric and elevated distal crossov
 ers. Interestingly total crossover events are the same between wild type a
 nd met1\, indicating that homeostatic mechanisms mediate remodeling\, incl
 uding crossover interference. Using 'pollen-typing' we have identified a d
 istally located intergenic crossover hotspot that shows elevated activity 
 in met1\, demonstrating that remodeling occurs via modulation of hotspot a
 ctivity. Together these data demonstrate how regional epigenetic organizat
 ion can pattern recombination frequency along eukaryotic chromosomes.
LOCATION:Department of Plant Sciences\, Large Lecture Theatre
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