Network calling network - how do two networks interact?

Pleiotropy is the property of genes affecting multiple functions or characters of an organism. Several genome-wide studies in yeast have borne light on the nature and extent of pleiotropy and have identified functional classifications of these genes. In a cell, mitochondria integrates many inputs to regulate cellular energy metabolism. Variation upstream of mitochondria is important to determine these differential responses. How genetic variation at DNA level translate to differential modulation mitochondrial function? This is important to determine how genetically variable organisms adapt to differential nutrient and stress conditions.

To comprehensively understand the genetic basis of gene-gene interactions, which can be either additive or epistatic, one has to determine the molecular mechanisms underlying these interactions. Since each of the gene has an underlying functional network, it becomes difficult to clearly determine these network network interactions. Using yeast system, it is possible to determine these individual functional networks. How do these networks interact when the two genes are additively interacting or when they interact epistatically? This will give insights into the molecular basis of additivity and epistasis and form the basis for understanding gene-gene interactions in quantitative traits.