This interaction is evident when two different genotypes are seen to respond to environmental variation in different ways. The genotype is the part of the genetic makeup of a cell, and therefore the whole organism, which determines a characteristic of said organism. Genotype is one of three factors that determine phenotype along with inherited epigenetic factors and the non-inherited environmental factors that are in focus in GxE. Epigenetic factors are heritable but are not a result of alterations in the DNA sequence.