CNN - Life on Earth began in the water. When animals moved onto the ground, they switched fins for limbs. How exactly that might have happened hundreds of millions of years ago, however, has long been an evolutionary mystery that has puzzled scientists. Now, US scientists say they may have stumbled on a possible answer.By tweaking a single gene, researchers at Harvard University and Boston Children's Hospital have engineered zebrafish that showed the beginning of limblike appendages.
To answer how animals made the transition from sea to land, scientists have traditionally looked to the fossil record. But in the past 30 years, scientists have searched for changes in genes that can account for the shift from fin to modern limb. "Most surprising to me is that such a dramatic change to the fin skeleton and musculature is possible with just a single mutation," said Brent Hawkins, a postdoctoral researcher at Harvard University and Boston Children's Hospital
