The idea of “dark matter” may send your mind to astronomy (or at least science fiction), but plant scientists have discovered what they’re terming “dark matter” in the maize genome.  This new discovery is a tiny percentage of regulatory DNA, and accounts for approximately half of the variations in observable traits that occur in corn.

Cornell University and Florida State University researchers believe they have found 1 to 2 percent of the maize genome that turns genes on and off in the DNA.  This new discovering would allow breeders to develop traits much more efficiently.

“It allows us to start pinpointing the single base pair changes small mutations that are regulating or allowing plants to adapt to their environment. It helps us narrow down the hunt dramatically,” said Edward Buckler, a Cornell University and U.S. Department of Agriculture (USDA) research geneticist and a co-author of the May 16 paper appearing in Proceedings of the National Academy of Sciences.

Most DNA, including all the genes that code for proteins, is tightly coiled up to fit inside the nuclei of cells. For example, if you stretched DNA strands found in one human or corn cell all the way out, they would measure 2 meters. Yet when coiled in a nucleus, the genetic material is compacted nearly a millionfold. But there are also regions of DNA that are not tightly wrapped, known as open chromatin.

The researchers identified areas of open chromatin that regulate genes. The discovery was made possible by a single cost-effective chromatin profiling procedure to measure how tightly wrapped DNA is everywhere in the genome, developed by Vera and Bass.

This new technology could be so efficient in pinpointing specific regions in DNA that the technique could be used in hundreds of crops.

“It’s like finding a light switch on the wall,” Hank Bass, an associate professor of biology at Florida State University and one of the study’s co-authors said. “The chromatin profiling shows you which parts of the genome are genetic switches.”

You can read more about this landmark finding on the Cornell Chronicle.