This definition you provide... Epigenetics is the study of changes in organisms caused by modification of gene expression. ...is not sufficient. The crux of e

This definition you provide... Epigenetics is the study of changes in organisms caused by modification of gene expression. ...is not sufficient. The crux of epigenetics is that it involves >heritable< changes in gene expression. At least that's what it originally meant. Now I feel like the definition is transforming into the definition you gave. However the author of the smithsonian article is confusing the two usages, because in several places the article alludes to the heritability.