Analysis of Epistasis in Natural Traits Using Model Organisms.

The ability to detect and understand epistasis in natural populations is important for understanding how biological traits are influenced by genetic variation. However, identification and characterization of epistasis in natural populations remains difficult due to statistical issues that arise as a result of multiple comparisons, and the fact that most genetic variants segregate at low allele frequencies. In this review, we discuss how model organisms may be used to manipulate genotypic combinations to power the detection of epistasis as well as test interactions between specific genes. Findings from a number of species indicate that statistical epistasis is pervasive between natural genetic variants. However, the properties of experimental systems that enable analysis of epistasis also constrain extrapolation of these results back into natural populations. Highlights Identification of statistical epistasis in natural populations remains challenging due to the relationship between allele frequency and statistical power. Artificial populations have been constructed in model organisms to detect statistical epistasis between two regions of the genome; however, it is difficult to use these results to understand how epistasis operates in natural populations. Studies of focal perturbations in defined genetic backgrounds suggests that natural selection can influence the types of nonadditive relationships that exist. [ABSTRACT FROM AUTHOR]