Epigenetics plays an important role in development and stem cell differentiation, as well as having a significant impact on human disease. The necessity to retain gene expression patterns in both stem/progenitor cells and their differentiated progenies is the epigenetic underpinning of stem cell differentiation. Genes associated with self-renewal are down-regulated as a stem cell develops, while lineage-specific genes are activated.
Genetics research is unique in that the findings apply not only to the proband but also to her lineage in the past and future. When stem cells are genetically modified, they can be used to improve cell survival when transplanted, especially in a hostile environment. They can be modified to transfer proteins to nearby cells, destroy cancer cells, or decrease graft-host rejection.