Ortrun Mittelsten-Scheid spoke about release of epigenetic silencing by transacting mutations. She described selecting for a mutation that relieved silencing of a hygromycin resistance gene. The hygromycin silencing was released by backcrossing to ddm1 mutants but not to antisense methyl transferase mutants. Jeff Jeddeloh described his work on combining a ddm1-2 mutation with a silenced PA12 gene complex. The ddm mutation affects gene silencing and methylation immediately and progressively suggesting a model for the effects seen in ddm1 inbred lines where phenotypes can progess over generations and appear cumulative.
Similar changes occur in the superman alleles seen in the antisense methyl transferase lines.
He talked about DNA binding proteins that enhance the binding of other transcription factors such as proteins that contain Dof domains, which interact with B ZIP binding factors. Finally, Chris Makaroff discussed his characterization of syn1 a synaptic mutant. He presented beautiful pictures of meiosis of both wild type and mutant plants which suggest synapsis was defective and unpaired chromosomes persist through the second meiotic division. This technique will also be important in looking at other mutants altered in meiosis.