So too with poo. A poo can take on a variety of appearances and still be considered normal. It can be all manner of shades â from orangey and dark brown to magenta or green from certain veggies or blue from artificially-colored foods and beverages.
Epigenetics is the study of changes in gene activity which are not caused by changes in the DNA sequence. It is the study of gene expression, the way genes bring about their phenotypic effects. These changes in gene activity may stay for the remainder of the cell's life and may also last for many generations of cells, through cell divisions.
A consensus definition of the concept of epigenetic trait as stably heritable phenotype resulting from changes in a chromosome without alterations in the DNA sequence was formulated at a Cold Spring Harbor meeting in 2008, although alternate definitions that include non-heritable traits are still being used.