Researchers studied the thale cress (an
“These tough little plants can become little genetic adaptation machines which allows them to invade hostile environments and even thrive where others can’t. In fact, a large proportion of the most invasive plant species in the world are genome doubled, so we
hypothesisedthat there are adaptations that occur as a result of genome duplication that we can focus on and find the genes responsible for the adaptations. To test this hypothesis in this study, we resequenced about 300 genomes of this little plant Arabidopsis arenosa ,collectedfrom 39 geographical areas across Europe, and looked for the little footprints of selection, a particular gene, that appeared helpful for adaptation to a particular area.”
“In addition to particular genes, we found something even more significant –
thatin the genome doubled variants the fundamental processes governing how Darwinian selection operates appear a bit different to how they are in the single genome species. That is, we found broader reasons why genome doubled populations may adapt better that go beyond the fact that they simply have more DNA or might harbournew gene variants.”
They found that in doubled genome versions of a species the linkages between
neighbouringgenes on the same strand of DNA are less strict. It was more common for two genes near one another on a particular piece of DNA to have different combinations of mutations than it was in single genome versions of the species. It may be that this process of ‘linkage breaking’ between neighbouringgenes is more efficient in the doubled genome species because a greater variety of different combinations are present and the DNA recombines with additional partners, generating novel combinations of genes. This means that good versions of one gene can escape from bad versions of another genesin its ‘DNA neighbourhood‘, allowing Darwinian selection to occur more efficiently, purging from a population the bad versions and selecting the good. Emma Rayner, “Two genomes can be better than one for evolutionary adaptation, study finds” at Phys.org
This is very interesting but it’s not clear that it is only a Darwinian process. Genome doubling doesn’t usually work well at all in wild nature, let alone solve all kinds of problems (“This means that good versions of one gene can escape from bad versions of
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See also: Polyploidy: Genetic Fundamentalism Is Still Looking For A Job?
New species originated via polyploidy?
Genome doubling (polyploidy) a key factor in evolution?
Life continues to ignore what evolution experts say