University of Southern California
Ray R. Irani Hall
Molecular and Computational Biology
Computational Biology Colloquium
Johannes Kepler University,
Institute of Biophysics
"How meiosis drives the sequence evolution
at recombination hotspots"
Abstract: Meiosis is a potentially important source of germline mutations, as sites of meiotic recombination experience recurrent double-strand breaks (DSBs). However, evidence for a local mutagenic effect of recombination in population sequence data has been equivocal. By sequencing a large number of single crossovers obtained from human sperm, we find that recombination is mutagenic. Crossovers harbor more de novo mutations than non-recombinants, primarily CG to TA transitions enriched at CpG sites. Such striking asymmetry of mutational patterns is not seen genome wide, but could be predominant in mechanisms involving single stranded DNA processing. Our large data set also provides new evidence that the transmission of GC-alleles is favored during crossing-over and shows that GC biased gene conversion (gBGC) is a strong driver of hotspot sequence evolution opposing mutation. This is consistent with the idea that gBGC could be an adaptation to counteract the mutational load of recombination.
Thursday April 9, 2015
Host: Norm Arnheim and Peter Calabrese