When they compared the tree diagrams of the embryonic stem cells, neuronal progenitors and neurons they saw that during differentiation, many of the long-range contacts remain in place. However, other regions form new contacts, again based on common features. "Changes in gene activity correlate with changes in the spatial organization," Schuler says. The scientists believe that in the future, this map of contacts might be used to help find the causes of genetic diseases. On the one hand, it could be used to localize chromosome rearrangements that play a role in conditions such as cancer. On the other, it might be possible to identify genes that are responsible for congenital diseases. This has been one result of numerous genome-wide studies carried out in recent years that have linked mutations to various diseases. However, for many of these genetic variants, the means by which they cause the particular disease has been unclear. They might, for example, change gene interactions instead of the genes themselves. "Our maps increase the pool of targets on DNA that might be affected by a single mutation," Pombo says.
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