Chickens and other birds are thought to have descended from dinosaurs through a series of genetic changes. Scientists have rewound 65 million years of evolutionary history by tweaking chicken DNA to create embryos that grow alligator-like snouts rather than beaks.
But by altering the DNA of chicken embryos in the early stages of their development, scientists are able to undo the progress made by evolution and give them qualities they lost millions of years ago.
Ethical regulations prevent the eggs from being hatched but Arhat Abzhanov, an evolutionary biologist based at Harvard University in America, said he hopes to one day to complete his work by turning chickens into Maniraptora, small dinosaurs believed to have spawned 10,000 species of birds.
The ability to rewind evolution also raises the prospect of fast-forwarding the same process to create species which are designed to adapt to Earth’s changing climate, and eliminating birth defects in human children, it was claimed.
Scientists believe that modern birds lost their snouts in the cretaceous period, instead developing beaks in one of a number of changes that distances them from other relatives like alligators.
But by altering parts of their DNA to resemble alligator genes before the beak began to develop, Dr Abzhanov was able to alter the development of chicken embryos so that they grew snouts instead.
The growth of embryos is governed by signalling molecules, which switch on certain genes controlling the development of limbs, organs and other body structures.
Adding proteins that stifle signalling molecules to the centre of the embryo’s face prevented them from developing beaks, leaving separate molecules on the sides of the face free to grow into snouts by their 14th day of gestation.
Dr Abzhanov told the New Scientist magazine: “It looks exactly like a snout looks in an alligator [at this stage].”
Jack Horner, a leading paleontologist based at the University of Montana, is conducting a similar project aimed at developing a “chickenosaurus” with a tail and hands similar to those of a dinosaur.
If scientists are able to turn the process around and speed up evolution, they could create species better adapted to the changing planet.
Craig Albertson, a developmental biologist from the University of Massachusetts, has already crossed two blue fish from different populations to create red offspring – a possible evolutionary trait making it easier for males to attract females in murky, polluted water.
Understanding exactly how genetic signalling works could also help doctors prevent birth defects such as cleft palate from developing in the womb, it was claimed.
Jill Helms, a stem cell biologist based at Stanford University in California, said: “I can envision a day when we eliminate such defects in the womb.”
Via Telegraph
