Frozen Evolution. Or, that’s not the way it is, Mr. Darwin. A Farewell to Selfish Gene.

The existence of internal periodicity permits the functioning of a very interesting mechanism of the formation of new genes.The classical model assumes that a new gene encoding a protein that is capable of performing a particular new function is formed by gradual slow accumulation of point mutations in an older gene.However, the sequence of new genes would be changed very slowly in this way and the new variants would differ from the older variants only in substitution of a single aminoacid and thus it can hardly be expected that the new protein would be able to perform a function differing in principle from the old one.However, a mechanism does exist, through whose effect a single mutation simultaneously changes the sequence of all the aminoacids in the protein.This is a frameshift mutation.s

            If a reading-frame shift occurs as a consequence of insertion or deletion of a single nucleotide in the chain, almost the same sequence of RNA nucleotides will be translated as a sequence of completely different nucleotide triplets (codons) into a completely different sequence of aminoacids in the resultant protein.If genes did not exhibit any internal periodicity, then the probability that one DNA chain would encode, in two different reading phases, two longer continuous proteins, i.e. would simultaneously contain two longer open reading frames, i.e. sections of nucleotides not containing any of the three termination codons, would be negligibly small.

            However, because of the periodicity of genes, this situation does actually occasionally occur.At the present time, at least one case is known in which a new gene was most probably actually formed by this mechanism.This consists in the formation of the enzyme for the hydrolysis of oligomers of 6-aminohexanic acid in Flavobacterium sp. KI72, bacteria that adapted to life in waste waters generated in the production of nylon (Ohno 1984a).