Could there be forbidden sequences in the genome - ones so harmful that they are not compatible with life? One group of researchers thinks so. Unlike most genome sequencing projects which set out to search for genes that are conserved within and between species, their goal is to identify "primes": DNA sequences and chains of amino acids so dangerous to life that they do not exist.
"It's like looking for a needle that's not actually in the haystack," says Greg Hampikian, professor of genetics at Boise State University in Idaho, who is leading the project. "There must be some DNA or protein sequences that are not compatible with life, perhaps because they bind some essential cellular component, for example, and have therefore been selected out of circulation. There may also be some that are lethal in some species, but not others. We're looking for those sequences."
Hampikian believes the applications of his work could be wide-ranging. He has already received a $1 million grant from the US Department of Defense to develop a DNA "safety tag" that could be added to voluntary DNA reference samples in criminal cases to distinguish them from forensic samples. Such tags would not necessarily have to consist of lethal sequences, but could be based on primes that would be easy to detect using a simple kit.
Further down the line there is the possibility of constructing a "suicide gene" to code for deadly amino acid primes. It could be attached to genetically modified organisms and activated to destroy them at a later date if they turned out to be dangerous, Hampikian suggests.