Research finds the evolution of stick insects and species formation can be repeatable and predictable
International team studied whole-genome divergence between replicate pairs of stick insect populations that have adapted to different host plants
Study showed the repeated component of the genome evolution occurred by Darwinian natural selection
Findings demonstrate a repeatable element to evolution, even at the genome-wide level and during the complex process of the formation of new species
The formation of new species and genome evolution in stick insects can be repeatable and predictable, researchers from the University of Sheffield have found.
As populations diverge to form news species their genomes also diverge, but whether these processes can be repeated and predicted has remained debated.
A team of scientists from leading universities across the world studied Timema cristinae, a wingless, herbivorous stick insect endemic to California that has repeatedly evolved ecotypes adapted to different host plant species and are in the process of evolving into two unique species.
They examined whole-genome divergence between replicate pairs of stick insect populations that have adapted to different host plants and conducted a field experiment to test if repeatable genome evolution was caused by Darwinian natural selection.
Their study, the first of its kind, showed the repeated component of the genome evolution occurred by natural selection, while its collective findings demonstrate a repeated element to evolution, even at the genome-wide level and during the complex process of the formation of new species.
The study, published in the journal Science today, advances understanding of biological diversification.
Dr Patrik Nosil, of the University of Sheffield’s Department of Animal and Plant Sciences, is the senior author of the paper.
He said: “As organisms colonise new environments, they either adapt to these environments or go extinct.
“Our laboratory studies this process of evolutionary adaptation and its consequences. For example, we test how rapidly adaptation can occur, how repeatable the process is, and what types of genetic changes are involved. In turn, we examine whether adaptation creates new species.
“We resequenced the genome of each individual that we collected and looked at which genes were differentiated between populations adapted to different host plants. Because we also conducted an experiment in the field measuring evolution in real time, we gained information on how natural selection is pulling these populations apart."
Scott Egan, from Rice University in the USA, said it was previously impossible to conduct this kind of study because of the expense of genomic tests.
He added: "The world of genomics is beginning to open up for people like me who don't study model organisms
"This is allowing us to address, in new ways, questions that Charles Darwin posed over 150 years ago."
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