Eric Lai, PhD – Developmental Biology Program, Memorial Sloan Kettering Cancer Center — CSB Seminar

CSB Departmental Seminar

Friday, April 24th @ 11:00 am

SPEAKER: Eric Lai, PhD – Developmental Biology Program, Memorial Sloan Kettering Cancer Center

TITLE: Genomes in conflict: The biology of endogenous RNA interference and meiotic drive

ABSTRACT: Selfish meiotic drive systems (SMDs) can distort progeny sex-ratio (SR) and/or induce sterility. If left unchecked, the activity of SMDs can collapse the population, and potentially cause extinction. Although widespread in nature, the molecular mechanisms of SMDs, and how they are silenced to restore Mendelian segregation, remain largely mysterious. Importantly, their rapid evolution means that classic model organisms may not be suited to reveal their fundamental features, breadth and impact. Instead, we used non-model Drosophila species to uncover critical roles for endogenous RNA interference (RNAi), via hpRNA class endo-siRNAs, to suppress incipient sex chromosome conflicts. Genetic studies reveal that these involve de novo meiotic drive loci encoded by the X chromosome. Furthermore, long read genomic data from wild fly lines reveals extraordinary polymorphism and copy number variation in these genes across individuals. We interpret this to reflect an ongoing arms race between SMD distortion and suppression by small RNAs. Beyond hpRNAs, we find evidence for a broader set of endogenous siRNAs produced from diverse types of double stranded RNA, and show that these are also fast-evolving and have regulatory impacts. Overall, our studies highlight the genetic and molecular importance of RNA silencing during recent or active speciation.

HOST: Co-host with CSDB, CSB Trainee host: Una McNally – Harris lab

LOCATION: Cell and Systems Biology, 25 Harbord Street, Suite 432

LIVESTREAM LINK: https://csb.utoronto.ca/live-stream/