Glad we are talking about this…
No need to believe us (though we did warn you):
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.
Over time, genes change via random mutations. Some of these changes result in serious defects and are rarely passed on to the next generations, others have little impact, and others confer significant advantages, which become favoured due to natural selection and end up being passed on to future generations. This is the main source of genetic novelty and how organisms differ from each other. However, genetic novelty can also be generated by totally new genes evolving from scratch.Trinity College, Dublin, “Genes from scratch: Far more common and important than we thought” at ScienceDaily
Mmm, yes. It used to be called creationism but at one time creationism had a had reputation…
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. For example, a gene that is unique to cod fish living in the arctic allows them to survive in sub-zero temperatures.”
Orphan genes pose a tough evolutionary problem though. They don’t look like other genes, so where do they come from? One idea is that they can originate seemingly from nothing: over long, evolutionary timescales, a completely novel gene can emerge de novo out of a region in the genome that is made up of junk DNA. Alternatively, with enough time, two ‘cousin’ genes can diverge so much that we can no longer identify the relationship between them. Thus, a gene may at a glance appTrinity College,Dublin, “Genes from scratch: Far more common and important than we thought” at ScienceDaily
Anyone following the junk DNA scene will discover that the term is now frowned on. There isn’t very much junk DNA. Mind you, if “junk DNA” produces a useful gene, it shouldn’t be classed as junk anyway, right?
Okay, read on …
For a long time, scientists thought the majority of orphan genes were simply cases of ‘missing relatives’, which could be explained by the divergence of the sequences through mutations during evolution. The new research suggests this is not the case.
Aoife McLysaght, professor in genetics at Trinity College Dublin, said: “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.”Trinity College,Dublin, “Genes from scratch: Far more common and important than we thought” at ScienceDaily
This is special:
Anne-Ruxandra Carvunis, Ph.D., assistant professor of computational systems biology at the University of Pittsburgh, said:”Order seems like something that’s hard to achieve, but our results go completely opposite to that. 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.”Trinity College,Dublin, “Genes from scratch: Far more common and important than we thought” at ScienceDaily
“Rampant” order? “Rampant” is a word we associate with disease; it’s not a word we commonly associate with “order.” On the other hand, an order that frustrates the outworkings of Darwinian evolution in favor of an orderly system that produces needed innovations must seem a lot like a disease to some. 😉
Paper at Nature (open access)
Also a paper at life (open access).
Hat tip: Philip Cunningham