Everything you thought you knew about the shape of DNA is wrong
When you get down to the core of life, it’s just a game of origami.
For the latest episode of “Science Happens,” I visited Job Dekker, a biologist at the University of Massachusetts Medical School, who is on the cutting edge of research into our inner origami. At the Center for 3D Structure and Physics of the Genome, Dekker and his colleagues are figuring out the marvelously complex shape of DNA. Some day, this research could provide us with a new way of thinking about how our genes influence our health.
We each have about 20,000 genes, all of which sit together on a molecule of DNA. One of the great discoveries of the 20th century was how the shape of DNA allows those genes to work. Each DNA molecule is actually a pair of strands wound together, forming a double helix. To make a protein from a gene, a cell must separate the strands and read their sequence. To reproduce, a cell must rip the strands apart and build new counterparts for each one.
Biology textbooks teach these fundamental rules of life with a simple diagram showing DNA looking like an abstract spiral staircase. But reality is far messier. Each DNA molecule is six feet long. Our cells have to wind it tightly to fit in their interior — without tangling them in knots in the process. In fact, our cells have to unfold and refold DNA in order to read their genes.
In recent years, scientists have made tremendous progress in reading the sequence of our DNA. But the three-dimensional shape of DNA remains mostly mysterious. In fact, it’s only recently that scientists have even begun to get a glimpse at how our DNA is folded.
Today, scientists focus on the ways that gene mutations cause diseases like cancer. But totally normal genes can still malfunction if they get folded in the wrong way. It’s possible that the research going on in Dekker’s lab may eventually reveal a hidden world of “folding diseases.”
Carl Zimmer can be reached at email@example.com