Study finds why some people walk on all fours
The discovery throws light on how humans are able to walk on two feet
Monday, 02, Jun 2008 09:40
Scientists say they have discovered the gene that causes some people to walk on all fours (quadrupedality) rather than upright.
In 2005 four quadrupedal families were discovered in Turkey living in isolated villages 200 to 300km apart.
Their genetic information has since been studied by researchers at Bilkent University, Ankara.
They found that the affected individuals in two families had mutations in the gene responsible for the expression of very low density lipoprotein receptor (VLDLR), a protein which is known to be critical to the proper functioning of the cerebellum (a part of the brain involved in motor control) during development.
"We carried out genome-wide screening on these families and found regions of DNA that were shared by all those family members who walk on all fours," said Professor Tayfun Ozcelik.
"However, we were surprised to find that genes on three different chromosomes are responsible for the condition in four different families."
They also discovered that parents in one family had unsuccessfully tried to discourage their children from walking on all fours, suggesting social factors are unlikely to be involved in the development of quadrupedal locomotion.
The researchers say their discovery could help scientists understand how humans, unlike other primates, are able to walk for long periods on only two legs.
Along with brain enlargement, speech, and the ability to make tools, upright walking has long been regarded as one of the key traits that have led to modern humans.
Professor Ozcelik's team claim they have opened a window on how mutations in VLDLR affect brain development and influence gait in humans.
The research was presented today at the annual conference of the European Society of Human Genetics.