All About Mutations
Part 6

What it means to have a mutation and what role mutations play in Huntington’s disease.

What is a hairpin and how does it affect mutations?

When a single strand of DNA curls back on itself to become self-complementary, the result is a partial double helix with a bend in it. The structure is called a hairpin, and as as you can see from Figure Q-6, it looks just like one.

Hairpins may be the missing piece in the mutation puzzle. The reason researchers are so intrigued by hairpins is that they only form in the codon repeat regions of diseases in which expansion is seen (HD, of course, is one of these diseases). This specificity suggests that hairpins play a role in expansion. The big question is exactly how they do this. While many explanations have been put forth, the most popular one seems to be that hairpins aid in polymerase slippage.

Below we discuss a proposed model:

• The Hairpin-Mediated Polymerase Slippage Model

Last Modified: 1-28-04

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