/ Research finds evolution of stick insects and species formation can be repeatable and predictable

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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.Timema cristinae

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."

Additional information

The University of Sheffield

With almost 25,000 of the brightest students from around 120 countries, learning alongside over 1,200 of the best academics from across the globe, the University of Sheffield is one of the world’s leading universities.

A member of the UK’s prestigious Russell Group of leading research-led institutions, Sheffield offers world-class teaching and research excellence across a wide range of disciplines.

Unified by the power of discovery and understanding, staff and students at the university are committed to finding new ways to transform the world we live in.

In 2011 it was named University of the Year in the Times Higher Education Awards and in the last decade has won four Queen’s Anniversary Prizes in recognition of the outstanding contribution to the United Kingdom’s intellectual, economic, cultural and social life.

Sheffield has five Nobel Prize winners among former staff and students and its alumni go on to hold positions of great responsibility and influence all over the world, making significant contributions in their chosen fields.

Global research partners and clients include Boeing, Rolls-Royce, Unilever, AstraZeneca, Glaxo SmithKline and Siemens, as well as many UK and overseas government agencies and charitable foundations.

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