Research interests

Causes and effects of recombination rate evolution:

Allelic exchange through crossing-over of homologous chromosomes is essential to the fitness and diversity of species. In the absence of recombination, chromosomes are unable to uncouple deleterious and beneficial mutations causing the irreversible accumulation of the detrimental alleles. This process, known as Muller's ratchet, is one of the main causes of the degeneration of nonrecombining heterogametic sex chromosomes (Y and W) and can ultimately lead to extinction. For recombining chromosomes, differences in the rate of recombination have significant influences on the tempo of evolution. For example, haplotype blocks from selective sweeps are expected to be small when recombination rates are high. Recent studies have shown incredible amounts of variation in recombination rate between and within species. I am, in particular, interested in the absence of male recombination in Drosophila and genetic basis of the variability of recombination rates.

The interaction between repetitive elements and host genome:

Repetitive elements are selfish sequences that amplify in the genome often to the detriment of the host. Failure to repress their activity can lead to an on-slaught of detrimental mutations including insertions disrupting gene function and ectopic recombination causing large scale rearrangements. Suppression is primarily achieved in two ways: post-transcriptional degradation of the transcripts via the piRNA pathway and transcriptional silencing through compacting the chromatin into unaccessible heterochromatin. However, host genome is constantly under the assualt of exotic (through horizontal transfer) or variant (mutations) repetitve elements that can escape suppression, and is under selection to continuously evolve and update its defense. I am interested in both sides of this armsrace. For my graduate dissertation, I focused primarily on one class of repeats known as simple satellites; they are highly repetitive sequences with short motifs that can stretch for megabases in the genome. Using k-seek, which de novo identifies and quantifies simple satellites from short reads, I characterized the simple satellite landscape both within and between species. Currently, I am working on understanding the establishment and regulation of heterochromatin during Drosophila development.