Meeting Abstract

54.1  Tuesday, Jan. 5  Programmed genome dynamism and its evolutionary cooption in a basal vertebrate AMEMIYA, Chris T.*; SAHA, Nil Ratan; SMITH, Jeramiah J.; Benaroya Research Institute; Benaroya Research Institute; Benaroya Research Institute camemiya@benaroyaresearch.org

While trying to understand how genomic rearrangements occur during the diversification of an immune receptor system in the sea lamprey (Petromyzon marinus), we serendipitously discovered unprecedented numbers of cells undergoing double-stranded DNA breaks in many embryonic stages. The meaning of these breakage events was unclear, but when considered with other pieces of data on DNA content and DNA Southern blot hybridization, it became evident that the lamprey undergoes significant DNA losses (rearrangements) during early embryonic development. These rearrangements do not occur in the germline, only the soma. Furthermore we have demonstrated that these rearrangements are tightly regulated, occur very early in development and result in the loss of specific transcribed genes. In this presentation we will discuss the developmental and evolutionary ramifications of this genome dynamism and present a model by which this genomic rearrangement process may be a significant driving force for regulating the genome.