Genomic 'Dark Matter' Identified

Following a painstaking study, investigators were recently able to identify the exact area of the human genome that determines the location and time when genes are turned on and off. The international group of scientists that conducted the research analyzed multiple animals species for this work.

Scientists at the Broad Institute and the Massachusetts Institute of Technology (MIT), in Cambridge, were responsible for coordinating the investigation, details of which appear in the October 12 online issue of the top scientific journal Nature.

In order to arrive at the new conclusions, geneticists had to cross-reference the genome of no less than 29 mammalian species. Eventually, this enabled them to discover the largest portion of dark matter in the human genome to date.

In the near future, the new data will be used to gain a deeper understanding of how many human diseases form, and then maybe develop new treatments and cures based on this information. A vast array of conditions is triggered by only slight modifications in our genetic material.

“With just a few species, we didn’t have the power to pinpoint individual regions of regulatory control,” explains Manolis Kellis, the Karl R. Van Tassel Career Development associate professor of computer science at MIT. The expert was also a co-author of the Nature paper.

“This new map reveals almost 3 million previously undetectable elements in non-coding regions that have been carefully preserved across all mammals, and whose disruptions appear to be associated with human disease,” the team member goes on to say.

In order to uncover these elusive genomic elements, the research team studies a wide variety of species, including elephants, bats, rabbits, lab mice and rats, and so on. In previous studies it became apparent that the number of genetic control mechanisms exceeded the amount of data the genes themselves had.

“Most of the genetic variants associated with common diseases occur in non-protein-coding regions of the genome. In these regions, it is often difficult to find the causal mutation,” research scientist Kerstin Lindblad-Toh explains.

She holds an appointment as the scientific director of vertebrate genome biology at the Broad Institute, and was also a coauthor of the new study. The expert also holds an appointment as a professor in comparative genomics at the Uppsala University in Sweden.

“This catalog will make it easier to decipher the function of disease-related variation in the human genome,” Lindblad-Toh explains. According to experts, it's likely that geneticists will be occupied with the new data for years to come.

“This paper represents the culmination of a major effort by three large-scale sequencing centers to annotate the genome using the powerful tools of comparative genomic analysis,” comments Harvard University professor of molecular and cellular biology William Gelbart, who was not involved in the study.