Meeting Abstract

P1.176  Saturday, Jan. 4 15:30  Nuclear Dualism as an Evolutionary Capacitor in Tetrahymena thermophila WEST, J.; University of Houston jwest5@trinity.edu

Tetrahymena thermophila has two distinct nuclei: a diploid germline micronucleus, which is transcriptionally silent during vegetative growth, and a polyploid (45C) somatic macronucleus, which determines the phenotype of the cell. During vegetative growth, the micronucleus stores genetic variation without it being exposed to selection. This variation is revealed via sexual reproduction, which is induced by environmental stress. Evolutionary capacitors are mechanisms that transiently express stored genetic variation. These mechanisms possess the following three characteristics: 1) genetic variation is hidden from selection, 2) hidden variation is revealed when it is most likely to be beneficial, and 3) revelation of variation is reversible. The dualistic nuclear architecture of Tetrahymena thermophila possesses these three characteristics, and may promote evolvability by functioning as an evolutionary capacitor.