Analysis of Properties of Heterochromatin Relative to Meiotic Recombination and Heterochromatic Gene Expression

To better understand the genetic properties of heterochromatin, I have pursued two avenues: meiotic recombination around the border of euchromatin and heterochromatin, and position effects at the heterochromatic light locus. Heterochromatin lacks recombination, and using meiotic recombination frequencies, I show that the recombination inhibition border concurs with the previously defined molecular border based on changes in histone proteins, specifically histone 3 methylation, characteristic of heterochromatin. I also show that the heterochromatic gene light behaves in a similar fashion to a previously studied heterochromatic gene, in that its function is impaired when moved out of the heterochromatic environment, but can be restored when brought near to large blocks of heterochromatin. These findings support the idea that gene function and recombination can be tightly controlled by the molecular environment of heterochromatin.