Media Releases

Between the genes — U of T researchers make sense of the “dark matter”

May 20, 2010

TORONTO, ON — A new dis­cov­ery by Uni­ver­si­ty of Toron­to sci­en­tists has uncov­ered the secrets behind what many in the field of mol­e­c­u­lar genet­ics have referred to as the mysterious“dark mat­ter” of DNA.

This “dark mat­ter” refers to what once thought of as noth­ing more than “junk DNA,” locat­ed in regions out­side of actu­al genes. When it was dis­cov­ered that genet­ic sig­nals, or tran­scripts, were com­ing from this area, many believed that there was a whole new mys­tery to solve, and that there was much more going on than orig­i­nal­ly expect­ed.

How­ev­er, a new study, led by Post­doc­tor­al Fel­low Harm van Bakel and Prof. Tim­o­thy Hugh­es from the Depart­ment of Mol­e­c­u­lar Genet­ics, has shown that most of these sig­nals are like­ly to be by-prod­ucts of sig­nals from already-known genes. Most of the oth­ers, the research indi­cates, are more back­ground noise than mean­ing­ful sig­nals.

“The mys­tery is solved,” says van Bakel. “Almost all of the ‘dark mat­ter’ has very lit­tle sig­nif­i­cance after all.”

Part of the mys­tery came from the method­ol­o­gy. Many reports of dark mat­ter sig­nals used “tiling arrays,” which the researchers deter­mined was cre­at­ing too many false pos­i­tives. By using a method of sequenc­ing large num­bers of RNA tran­scripts, a tech­nique that has only recent­ly been avail­able for a few years, they were able to deter­mine that unex­plained dark mat­ter only account­ed for 2 per cent of the total genet­ic sig­nal­ing, much less than orig­i­nal­ly believed. Of that 2 per cent, most are very close to one or anoth­er end of a gene, indi­cat­ing that they are like­ly copies of sig­nals expressed by the gene itself.

“Giv­en the mys­tery and nov­el­ty in the field of genet­ics, it’s impor­tant to know where to focus our search,” says van Bakel. “Up until now, we had no way of know­ing if we were miss­ing out on some key genet­ic infor­ma­tion con­tained in this dark mat­ter. This dis­cov­ery allows us to zero in on what is real­ly impor­tant.”

“The dark mat­ter tran­scripts are not sig­nals emerg­ing from a hid­den uni­verse with­in the genome,” says van Bakel. “It’s more like noise emit­ted by a busy machine.”


For more infor­ma­tion, please con­tact:

Chris Gar­butt
Senior Com­mu­ni­ca­tions Offi­cer
Temer­ty Temer­ty Fac­ul­ty of Med­i­cine