Boise State University researchers are searching for “primes”: DNA sequences and chains of amino acids so dangerous to life that they do not exist.

They have identified more than 60,000 primes of 15 nucleotides in length and 746 protein “peptoprime” strings of five amino acids that have never been reported in any species, and that represent the largest possible set of lethal sequences.

The next step is to test 20 of the peptoprimes in bacteria and human cells to see whether they have any effect such as causing death or provoking an immune reaction.