The Illustrated Guide to Epigenetics
February 8 2011
HOW DO HUNDREDS OF DIFFERENT TYPES OF CELLS ALL DEVELOP FROM THE SAME GENOME? THIS IS THE QUESTION DRIVING THE EMERGING SCIENCE OF EPIGENETICS. HERE’S WHAT YOU NEED TO KNOW.
What is epigenetics? Human life begins as a single cell equipped with all of the genetic information—known as the genome—it will need to develop into a full-grown adult. Through a process of repeated cell division, this cell eventually multiplies into tens of trillions of cells, each containing a complete copy of the genome. Despite having identical genetic information, these trillions of cells somehow develop into hundreds of different cell types—from brain to liver cells—that make up the human body (FIGURE 1). Figuring out how one genome can produce so many different types of cells is, in a nutshell, the project of a subfield of genetics known as epigentics.
Nucleosome: DNA coils around proteins called histones, forming a nucleosome. (Note: This is a simplified drawing. In reality DNA wraps twice around a core group of eight histones.)Illustrations by Joe Kloc.
