Data from: Random sequences are an abundant source of bioactive RNAs or peptides

It is generally assumed that new genes arise through duplication and/or
recombination of existing genes. The probability that a new functional
gene could arise out of random non-coding DNA is so far considered to be
negligible, as it seems unlikely that such an RNA or protein sequence
could have an initial function that influences the fitness of an organism.
Here, we have tested this question systematically, by expressing clones
with random sequences in Escherichia coli and subjecting them to
competitive growth. Contrary to expectations, we find that random
sequences with bioactivity are not rare. In our experiments we find that
up to 25% of the evaluated clones enhance the growth rate of their cells
and up to 52% inhibit growth. Testing of individual clones in competition
assays confirms their activity and provides an indication that their
activity could be exerted by either the transcribed RNA or the translated
peptide. This suggests that transcribed and translated random parts of the
genome could indeed have a high potential to become functional. The
results also suggest that random sequences may become an effective new
source of molecules for studying cellular functions, as well as for
pharmacological activity screening.