How do the two DNA strands separate? Is is active or passive? Is there some internal mechanism or is there some force from the outside?
Cornell University researchers have found that an enzyme called Helicase is the active force behind the unravelling of the two DNA strands.
This is a significant find because it explains how the separation occurs, from an outside force; but it also shows that defects in helicases can influence many human diseases, from a tendency or predisposition to cancer to premature aging.
The research occured by tying down the two strands separately and introducing the helicase enzyme. They found that the separation occured very quickly and they were able to measure the tension of the strand using a laser beam.
One effect on this is that the process of replication is understood, so one can see the effect it can have on genetic mutations. If the enzyme makes a poor separation, the DNA copy will not be a replica of the original. Hence a mutation will occur.
http://www.sciencedaily.com/releases/2007/07/070703172500.htm
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