An intense scientific debate has ignited around a quiet but extraordinary family living in rural Turkey-a family with five adults who walk on all fours.
Since bipedalism has long been considered one of the defining characteristics of anthropological, such a discovery raises fascinating questions about genetics, society, and the evolutionary history of our species.
Is this the anthropological find of the millennium, or simply a unique medical case? The three sisters and two brothers may offer insight into the way our apelike ancestors moved, according to scientists.
Human ancestors are believed to have begun walking on two legs more than three million years ago. The family's exact location and last name have not been disclosed. Born with a genetic brain abnormality, two of the sisters and one of the brothers are thought to have only walked on all fours their entire lives. The two other siblings can walk upright for short distances. The siblings' parents are closely related and have had 19 children in all.
This bizarre case is not a hoax, according to experts who have studied the family.
The cause of the four-limbed locomotion, however, is a bone of contention among the researchers.
Uner Tan is a neurophysiologist—a doctor specializing in the functions of the brain, spinal cord, and nerves—at Cukurova University in Adana, Turkey. He believes the siblings, who range in age from 18 to 34, are evolutionary throwbacks—a "missing link" to our forebears. (Related reading: "Was Darwin Wrong?") Meanwhile German geneticists believe the siblings' genetic abnormality may have knocked out the gene responsible for bipedalism, or two-legged walking, in humans.