A puzzle posed by segments of ‘dark matter’ in genomes — long, winding strands of DNA with no obvious functions — has teased scientists for more than a decade. Now, a team has finally solved the riddle.
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The results, published…in Cell, might help researchers to better understand neurological diseases such as Alzheimer’s. They also validate the hypotheses of scientists who have speculated that all ultraconserved elements are vital to life — despite the fact that researchers knew very little about their functions.
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In mice, [researcher Diane Dickel] deleted four ultraconserved elements — individually and in various combinations — that lie within regions of DNA that also contain genes important in brain development. Again, the mice looked okay. But when the investigators dissected the rodents’ brains, they discovered abnormalities.
Mice lacking certain sequences had abnormally low numbers of brain cells that have been implicated in the progression of Alzheimer’s disease. And those with another ultraconserved element edited out had abnormalities in a part of the forebrain that’s involved in memory formation, as well as epilepsy. …
Future studies might explore whether people with Alzheimer’s disease, dementia, epilepsy or other neurological disorders have mutations in these overlooked non-coding sequences. Although the functions of many other ultraconserved sequences remain unknown, [genomicist Gill] Bejerano feels confident that they, too, will prove essential.
[Editor’s note: Read the full study (behind paywall)]
Read full, original post: ‘Dark matter’ DNA influences brain development
