PgmNr P2091: The genetic basis of temperature sensitivity in a mutationally induced trait.

Authors:
Jonathan Lee 1 ; Matthew Taylor 1,2 ; Amy Shen 1 ; Ian Ehrenreich 1


Institutes
1) University of Southern California, Los Angeles, CA; 2) University of Washington, Seattle, WA.


Abstract:

Determining how genetic variation alters the expression of heritable phenotypes across conditions is important for agriculture, evolution, and medicine. Central to this problem is the concept of genotype-by-environment interaction (or ‘GxE’), which occurs when segregating genetic variation causes individuals to show different phenotypic responses to the environment. While many studies have sought to identify individual loci that contribute to GxE, obtaining a deeper understanding of this phenomenon may require defining how sets of loci collectively alter the relationship between genotype, environment, and phenotype. Here, we identify combinations of alleles at seven loci that control how a mutationally induced colony phenotype is expressed across a range of temperatures (21, 30, and 37°C) in a panel of yeast recombinants. We show that five predominant multi-locus genotypes involving the detected loci result in trait expression with varying degrees of temperature sensitivity. In analyzing the genetic basis of GxE in our system, we demonstrate that the involved alleles contribute to temperature sensitivity in different ways. While alleles of the transcription factor MSS11 specify the potential temperatures at which the trait can occur, alleles at the other loci modify temperature sensitivity within the range established by MSS11 in a genetic background- and/or temperature-dependent manner. We are now working to characterize how different combinations of these causal alleles modulate temperature sensitivity at the molecular and systems levels. Our goal is to establish a clear portrait of how genetic variation and the environment together alter global gene regulation, thereby resulting in GxE.