London: Ever wondered why does the left
side of the human brain control the right side of the body and vice-versa?
Well, scientists claim to have finally unravelled
the mystery, after they discovered a gene while studying the
basis of "mirror movement" disorders which affect a handful of
rare individuals, the `New Scientist` reported.
Mirror movement disorders fascinate neuroscientists
because they appear to arise from the sides of the brain
failing to connect to just one side of the body.
"It`s a problem where the brain, instead of being
selectively connected to the opposite side of the body, seems
to connect to both sides of the body," said Guy Rouleau, a
neurologist at the University of Montreal in Canada.
To understand the genetic basis of MM disorders,
Rouleau and his colleagues scanned the genes of members of
several generations of a Canadian family in which mirror
movement is common.
Those with MM disorders had a specific mutation in one
of their copies of a gene called DCC, thought to control the
routes that the developing nerve cells carve through the body.
The scientists found a different mutation in the DCC
gene in an Iranian family in which the disorder is common, but
in none of 538 unrelated people without mirror movements.
The team concludes that DCC protein is required during
development to coax nerve cells across the body`s midline, so
that left brain areas control the right side of the body and
vice versa. In people with just one working copy of DCC, only
some nerve cells get the message to cross the midline.
The findings have been published in the `Science`