DISSERTATION RESEARCH: Epigenetic Effects of an Invasive Parasite on an Avian Host

点击翻译按钮获取中文摘要

The goal of this research is to understand how processes that modify the function of genes without changing the DNA sequence affect the defense of Galapagos mockingbirds against an introduced and sometimes lethal parasitic fly. This modification may enable the host to respond quickly to parasitism and reduce its negative effects. The parasite lives in the nests of this and other species of birds in the Galapagos and feeds on nestlings, and is a threat to their survival. Studying how this modification acts as a rapid defense against parasites will provide insights into how animals adapt to new environmental threats. This project will involve training undergraduates in field biology techniques and scientific writing. It will also incorporate workshops for Galapagos National Park rangers and tour guides to help develop strategies for monitoring and controlling this pest species in the Galapagos.This project will analyze DNA methylation patterns of mockingbirds studied during four field seasons: two in which mockingbirds were tolerant to the fly parasite, P. downsi, and two in which the fly caused high mortality. During the field study, mockingbird nests were either fumigated with permethrin, a dilute insecticide, that killed the parasite, or sham-fumigated as a control, that let the nests be naturally infested. Growth, health and fledging success of parasitized and non-parasitized nestlings were compared and nestlings were sampled for blood twice during the nestling period. These blood samples, along with samples collected from study birds later recaptured as adults, will be analyzed for variation in methylation patterns. DNA methylation analysis will allow the researchers to identify genes that are affected by parasitism in tolerant vs. non-tolerant years as well as to investigate whether methylation alterations persist to adulthood and are potentially even heritable. The results of this research will provide new insights into epigenetic mechanisms of rapid adaptation in wild populations.