The Times March 07, 2006
Family that walks on all fours in Turkey (BBC)
Walking on all fours with the ancestors
By Sam Lister
FIVE brothers and sisters who can only walk naturally on all fours
are being hailed as a unique insight into human evolution, after
being found in a remote corner of rural Turkey.
Scientists believe that the family may provide invaluable information
on how Man evolved from a four-legged hominid to develop the ability
to walk on two feet more than three million years ago.
A genetic abnormality, which may prevent the siblings, aged 18 to 34,
from walking upright, has been identified.
The discovery of the Kurdish family in southern Turkey last July has
triggered a fierce debate. Two daughters and a son have only ever
walked on two palms and two feet, with their extended legs, while
another daughter and son occasionally manage a form of two-footed
walking. The five can stand up, but only for a short time, with both
knees and head flexed.
Some researchers claim that genetic faults have caused the siblings
to regress in a form of “backward evolution”. Other scientists argue
more strongly that their genes have triggered brain damage that has
allowed them to develop the unique form of movement.
But all agree that the family’s walk, described as a “bear crawl”,
may offer invaluable information on how our ape-like ancestors moved.
Rather than walking on their knuckles like gorillas and chimpanzees,
the family are “wrist walkers”, using their palms like heels with
their fingers angled up from the ground.
Scientists believe this may be the way hominids moved, allowing them
to protect their fingers for the more delicate and dextrous
manoeuvres so critical in the evolution of Man.
Nicholas Humphrey, evolutionary psychologist at the London School of
Economics, who has visited the family, said that the siblings
appeared to have reverted to an instinctive form of behaviour encoded
deep in the brain, but abandoned in the course of evolution.
“I do not think they were destined to be quadrupeds by their genes,
but their unique genetic make-up allowed them to be,” Professor
Humphrey said. “It is physically possible, which no one would have
guessed from the [modern] human skeleton.”
Professor Humphrey, who has been contributing to a BBC programme, The
Family that Walks on All Fours, to be broadcast on March 17, said
that weeks of study, and factors such as their hands’ shape and
callouses, showed that this was a long-term pattern of behaviour and
not a hoax. “However they arrived at this point, we have adult human
beings walking like ancestors several million years ago,” he said.
The siblings, who live with their parents and 13 other brothers and
sisters, are mentally retarded, as a result of a form of cerebellar
ataxia — an underdevelopment of the brain similar to that in cystic
fibrosis. Their mother and father, who are themselves closely
related, are believed to have passed down a unique combination of
genes resulting in the behaviour. While Professor Humphrey said that
cultural influences in their upbringing may have played a crucial
role, with parental tolerance allowing the children to keep to
quadrupedal walking, others believe that the cause is more purely
genetic.
Uner Tan, a professor of physiology at Cukurova University in Adana,
Turkey, who first brought the family to the attention of scientists,
argues that the gene mutations have made them regress to a “missing
link” primate state, also explaining their severe problems with
language. A team of German geneticists believes that the family holds
the key to a breakthrough gene for bipedality.
Researchers said that while the women affected, Safiye, 34, Senem,
22, and Amosh, 18, tended to spend their time sitting outside the
family’s basic rural home, one brother, Huseyin, 28, went into the
local village on all fours, where he could engage in basic interactions.
Jemima Harrison, of Passionate Productions, said: “They walk like
animals and that’s very disturbing at first. But we were also very
moved by this family’s tremendous warmth and humanity.”
http://www.timesonline.co.uk/article/0,,3-2072832,00.html
