Genome complexity: orphan genes have functions (Introduction)

by David Turell , Friday, February 21, 2020, 19:09 (1736 days ago) @ David Turell

This creates a problem for the theories of common descent in which all DNA must represent the past genomes:

https://www.sciencedaily.com/releases/2020/02/200218104740.htm

"Scientists from Trinity College Dublin and the University of Pittsburgh have discovered that de novo genes -- genes that have evolved from scratch -- are both more common and more important than previously believed.

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"the scientists devised a way of assessing just how frequently genes seem to evolve from scratch. Their results were surprising.

"Explaining de novo genes, first author on the paper, Nikolaos Vakirlis, Trinity, said: "Most of the genes in a genome have 'cousins' in the genomes of other species; genes made up of similar DNA sequences that, once translated into proteins, perform similar functions. However, some genes are unique and can only be found in a single, or small number of closely related species. We call these 'orphan genes' because they appear to have no relatives and are often responsible for unique characteristics and abilities of organisms.

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"'To our surprise, at most, around one third of orphan genes result from divergence. So, in turn, this suggests that most unique genes in the species we looked at are the result of other processes, including de novo emergence, which is therefore much more frequent than scientists initially thought."

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"...how can a gene that was never used before suddenly appear and play a major role?
This paradox can be resolved if emerging genes have high potential to be beneficial for the organism. So, while they are expected to play no particular role in their current form, random changes that affect their sequences or increase the amount of protein they produce when translated should lead to beneficial effects.

"The scientists tested whether this hypothesis may be true by doing a series of biological and computational experiments using baker's yeast as a model organism. And when they artificially allowed emerging sequences to be expressed at higher levels than they are naturally, the cells tended to grow faster.

"Importantly, growth was not enhanced by overexpressing established genes. So, emerging sequences do indeed carry the potential to be important to the cells.

"We found that simple order is rampant everywhere in the genome. The propensity to make simple shapes that are stable is already there, waiting to be exposed. De novo gene birth is thus becoming less and less mysterious as we better understand molecular innovation."

Comment: the bolds just an assumption based on hope and wishful thinking. Of course the useful orphans when useful were quickly expressed, but the study did not show why they should spontaneously appear from no antecedent DNA. True de novo is true de novo.