A new research asserts that ‘once a gene has morphed into its current state, the road back gets blocked’ which means that evolution marches on irreversibly with nary a step back.

Evolution entails bridge-burning, so to speak. The study, featured in the September 24 issue of the journal Nature, reveals ‘that over long time scales certain genetic blockades arise that make it nearly impossible to transform a modern protein into its ancestral state, even if ancient environmental pressures were to exist.’

According to study researcher Joe Thornton of the University of Oregon’s Center for Ecology and Evolutionary Biology and the Howard Hughes Medical Institute, “Evolutionary biologists have long been fascinated by whether evolution can go backwards. But the issue has remained unresolved, because we seldom know exactly what features our ancestors had, or the mechanisms by which they evolved into their modern forms.”

To arrive at the important conclusion, Thornton and his team studied evolution at the molecular level, ‘where they could figure out the steps taken between the ancestral form of a protein and its successor.’ The team studied the glucocorticoid receptor, ‘a protein that binds with the hormone cortisol and regulates stress responses, immunity and other bodily processes in humans.’

An independent opinion from Michael Rose, a professor of ecology and evolutionary biology at the University of California, Irvine, states “This is the best demonstration of the molecular foundations of evolutionary irreversibility that I have ever read.”

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Via Live Science