Genetic fluke may have led to humans walking upright

Small tweaks of one gene may have helped humans to walk upright.

Losing a genetic switch that increases production of a protein called GDF6 may have created the big toe and helped shape the human foot for bipedalism, scientists propose in a paper published online January 7 in Cell. “This change is one that makes all humans different from other animals,” says developmental geneticist David Kingsley, a Howard Hughes Medical Institute investigator at Stanford University.

The gene GDF6 makes a protein that helps control bone growth. Researchers had already established that the protein is important for proper skeletal development. It is one of a large group of proteins that sculpt the skeleton and control growth of other body tissues. GDF6 may also be responsible for some evolutionary changes in other mammals and fish, Kingsley and colleagues say...