Our Research


 We study the topics of telomere biology, cellular immortality, epigenetic inheritance, longevity, genome silencing and small RNAs using the nematode Caenorhabditis elegans as a model system.

C. elegans has a relatively compact ~100 MB genome whose sequence is completely assembled. We are interested in repetitive DNA, including the simple repeat sequence (TTAGGC)n present at C. elegans telomeres, which is closely related to the mammalian telomere repeat (TTAGGG)n. We are interested in the structure and regulation of telomeres, at genetic and epigenetic levels, and in the interplay between telomeres and internal segments of the genome. We recently identified two forms of transgenerational epigenetic inheritance at nematode telomeres, where high or low levels of single stranded telomere binding proteins can be transmitted for multiple generations. We wish to characterize these forms of epigenetic inheritance and their potential effects fitness. Psychosocial stress and space flight affect telomere length in humans, and we are interested in studying the interplay between telomeres, the long non-coding RNA transcribed from telomeres (TERRA), and stress response and longevity. The Ahmed lab has demonstrated that the Piwi/piRNA-mediated genome silencing pathway and telomerase promote germ cell immortality, and we remain interested in the heritable stress transmitted by Piwi/piRNA mutant germ cells, which can promote longevity, as well as novel pathways that allow germ cells to remain in a pristine immortal state.