DNA “spectral lines”
Elements can be detected in the solar energy spectrum because elements absorb specific wavelengths creating dark lines in the hot body radiation spectrum. By analogy “forbidden” DNA sequences would form “dark lines” in the expected DNA sequence frequency spectrum. Find interesting stuff by what is missing. Neat.
“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.”
4^15 is just over a billion. 20^5 is 3.2 million.
this seems fine as a way to derive unique sequences for tagging, but (1) is bound to high false negative rates due to sequencing errors (they exist) and (2) seems to ignore the fact that most of a (human) genome is expressed at extremely low levels (and thus unlikely to yield much of an RNA or protein effector for lethality)