Evolution of Earth: finding new genes (Evolution)

by David Turell , Tuesday, June 04, 2019, 21:03 (1997 days ago) @ David Turell

Fun and games in the lab. Using intelligent design to see how new genes might be made in DNA:

https://www.sciencedaily.com/releases/2019/06/190604131214.htm

"One key question in evolutionary biology is how novel genes arise and develop. Swedish researchers now show how new genes and functions that are advantageous to bacteria can be selected from random DNA sequences.

***

"Two different types of mechanism have been proposed: (1) new genes with novel functions arise from existing genes, and (2) new genes and proteins evolve from random DNA sequences with no similarity to existing genes and proteins.

***

"The raw material for the experiment was an big library of some 500 million randomised gene sequences, from which peptide sequences with a biological function were identified. In the experiment, random gene sequences were placed on a plasmid and overexpressed. The scientists then investigated whether they could give bacteria a specific, defined property. Were they, for example, able to give the bacteria antibiotic resistance? They identified several short peptides (22-25 amino acids long) that could give the bacteria a high degree of resistance to aminoglycosides, an important class of antibiotics used for severe infections.

***

"Through a combination of genetic and functional experiments, the scientists were able to demonstrate that the peptides cause resistance by attaching themselves to bacterial cell membranes and affecting the proton potential across the membrane. The disruption of the proton potential causes a decrease in antibiotic uptake, rendering the bacteria resistant.

"'This study is important because it shows that completely random sequences of amino acids can give rise to new, advantageous functions, and that this process of de novo evolution can be studied experimentally in the laboratory," says Dan I. Andersson, Professor of Medical Bacteriology, who is chiefly responsible for the study."

Comment: Just life origin of life designs in the lab, proving nothing about how evolution itself can find new genes for new functions.