PgmNr P321: Diverse genetic architectures lead to the same cryptic phenotype in a yeast cross.

Authors:
Ian Ehrenreich; Matthew Taylor; Joann Phan; Jonathan Lee; Madelyn McCadden


Institutes
University of Southern California, Los Angeles, CA.


Abstract:

Cryptic genetic variants that do not typically influence traits can interact epistatically with each other and mutations to cause unexpected phenotypes. To improve understanding of the genetic architectures and molecular mechanisms that underlie these interactions, we comprehensively dissected the genetic bases of 17 independent instances of the same cryptic colony phenotype in a yeast cross. In eight cases, the phenotype resulted from an interaction between a spontaneous mutation and one or more cryptic variants. The total number and specific identities of the detected cryptic variants depended on which gene was mutated. In the nine remaining cases, the phenotype arose without a mutation due to higher-order interactions only involving cryptic variants. These mutation-independent cases fell into two classes, which could be distinguished by the occurrence of recombination within a specific ~1.3 kb genomic interval in the promoter of a required cell surface protein. Our results may be relevant to other species and disease, as most of the mutations and cryptic variants identified in our study reside in components of the evolutionarily conserved and oncogenic Ras signaling pathway.