Textbooks have taught us that DNA is structured like a long, winding staircase. But we haven't known what it actually looks like — until now.
Scientists created the first 3-D structures of intact genomes — complete sets of DNA as they actually look in the cell. The images show how DNA folds to fit inside a cell's nucleus, which makes it look more like a wadded-up ball than the spiral strand we're used to seeing.
The 3-D structures add to previous research about how cells tightly wind DNA in order to fit it inside.
It's a delicate process. Each DNA molecule is about 6 feet long, but cells have to cram DNA into a tiny area without tangling it so that DNA can unfold and refold when cells read their genes.
The researchers say knowing exactly how DNA folds inside the cell will give them a better understanding of how specific genes interact and how the cell functions.