Finding DNA mutations in genes that cause or contribute to a disease is one of the most challenging tasks for a researcher, because the mutation could be anywhere in the 3.1 billion A, C, T and G molecules that make up our genome. It's like looking for a needle in a haystack, and scientist often don't even know where to begin looking. SNP analysis tells them what section of the genetic haystack to start looking in, and this allows them to find the disease-causing gene much more quickly.