22 June 2012
Maitreya Dunham
Department of Genome Sciences
University of Washington
I will talk about a proposed new mechanism of gene amplification in yeast. In continuous cultures propagated under low concentrations of sulfate, amplification of the transporter gene, SUL1, provides an enormous fitness gain. However, unlike the other CNVs that we have found during experimental evolution, SUL1 is not adjacent to any obvious repeat sequences that could explain its amplification. We sequenced a collection of independently evolved strains and discovered a novel inverted tandem repeat, flanked by short hairpins. The structure can't easily be explained by other known mechanisms of DNA rearrangement. We think that this event is created by a previously unrecognized error in replication, and that it may contribute to unexplained inverted repeats in other systems, including cancer.