New Genes

9 Jun 2019

At https://archaeologynewsnetwork.blogspot.com/2019/06/new-genes-out-of-not... ... how do new genes and functional proteins arise and develop? This is an important question to answer as far as evolutionary biology is concerned. In the latest piece of research the idea of new genes and protein arising from randomised DNA sequences has been explored. How does 'nothing' turn into a function affecting a small advantage that is favoured by natural selection? The raw material for the experiment was a library of 500 random gene sequences from which peptide sequences with a biological function were identified. In the experiment random gene sequences were placed on a plasmid and over exposed.

Note ... a plasmid is a small DNA molecule with a cell that is physically separated from a chromosomal DNA and can replicate independently. They are most commonly found in bacteria.

The scientists then investigated whether they could give give bacteria a specific defined property. Were they, for example, able to give the bacteria a high degree of resistance to aminoglycosids, an important class of antibiotics used for severe infections. They identified several short peptides, 22 to 25 amino acids long, that could give bacteria a high rate of resistance to anti biotics. They were able to confer resistance level 48 tim es higher and they demonstrated that the peptides cause resistance by attaching themselves to bacterial cell membranes and affecting the proton potential accross the membrane. The disruption of the proton potential causes a decrease in antibiotic uptake, rendering the bacteria resistant. The study shows random sequences of amino acids can give rise to new advantageous functions.