Our DNA is packaged up in long strings called chromosomes. Along these lengths are certain areas that are more fragile than others – like frayed points along a piece of string – that are prone to breaking. And broken chromosomes can cause big problems. Some of these fragile sites are due to short stretches of DNA being repeated many times over, which can be passed on through families. Now researchers have found a new region of repeated DNA close to a gene called Aff3. The gene is normally active in the developing paws, highlighted pink in this mouse embryo, and also in parts of the brain. But it gets shut down when the nearby DNA region is repeated. In humans, this region is associated with problems with language and movement, so understanding what's going on at a genetic level is helping to shed light on families affected by these conditions.
Written by Kat Arney
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