Duplicate genes help humans run long distances


Genetic evidence showing running is in our genetic heritage. This article references
a 2004 New Scientist article about human running ability which I excerpt at the
bottom.


http://www.newscientist.com/article/dn12381-duplicate-genes-help-humans-go-the-extra-mile.html
July 2007

Human beings can run long distances because we carry multiple copies of a gene
that helps supply our cells with energy, a new study suggests. That supports
the idea that endurance running gave our human ancestors an evolutionary edge.

An analysis of DNA from 10 primate species reveals that, compared with the genome
of chimpanzees and gorillas, our genome includes many more duplicates of a gene
called aquaporin 7 (AQP7), which transports water and sugary compounds into
cells. Humans appear to have five copies of this gene, whereas chimps have just
two, and other primates carry only one copy.
...
Given the potential influence exerted by extra gene copies, Sikela and his
colleagues wondered how humans might differ from other primate species in terms
of the number of duplicates we carry. The team extracted DNA from blood samples
taken from various primates including humans, along with chimpanzees, gorillas,
baboons, lemurs and several others.

The researchers calculated how many copies of various genes each species carries
with the help of DNA "micro-array" technology. If large quantities of the DNA from
a given genome attached to certain parts of the micro-array chip, this indicated
that it contained multiple copies of a specific gene.

After using this method to screen more than 20,000 genes, Sikela and his colleagues
found 84 genes for which the copy number in the human genome differs from that of
other primates.

The AQP7 gene in particular caught their attention. The protein made by the gene
functions as an important channel in the cell membrane. Specifically, the channel
allows water and a sugary compound called glycerol to enter the cell, where they
are used to produce energy. This has the potential to make a difference in long
bouts of exercise, when the body needs to mobilise energy molecules from fat
stores.

Given its role in transporting glycerol, the AQP7 gene "would certainly be a good
candidate to be involved in endurance running", says Sikela. He notes that recent
studies have suggested endurance running perhaps gave our ancestors an advantage
over other primates by enabling them to travel better across sweeping African
savannahs.
...



http://www.newscientist.com/article/dn6681-evolution-made-humans-marathon-runners.html
17 November 2004

We are born to run. According to new research, our bodies are highly evolved for
running long distances, an ability that allowed our ancestors to conquer the
African savannahs.

Proponents of the theory say that long-distance running may be an even more
significant evolutionary adaptation than bipedal walking, an ability which may
have emerged with the appearance of the first hominids some 6 million years ago.

It is true that we cannot keep up with the fastest four-legged mammals. The
speediest humans can sprint at barely 10 metres per second for just 15 seconds,
whereas horses and greyhounds can gallop twice as fast for many minutes.

Yet anthropologists, in focusing on this lack of short-term speed, have overlooked
how well adapted we are for endurance running, according to biologist Dennis
Bramble at the University of Utah, and his colleague Dan Lieberman of Harvard
University.

"Our legs are full of tendons that are not present in other primates," says
Lieberman. "You don't use your Achilles tendon when you walk," he says, but it
is essential for running. Our buttock muscles, whose large size is a distinctly
human attribute, are also vital for running, as they help stabilise the trunk
and prevent it pitching forwards.

These muscles too are barely used in walking. Runners also need to keep their
bodies cool, which could explain our large number of sweat glands and largely
hairless skin.

Many of these adaptations appeared with Homo erectus around 2 million years ago.
The long legs, short arms and low shoulders of H. erectus and later humans match
the demands of running, while in contrast, the limb proportions of the earlier
australopithecines were much closer to those of modern chimps, say Lieberman and
Bramble.

For example, compared with both chimps and australopithecines, humans have large
leg joints in proportion to body mass. These help dissipate the large impact
forces generated by running.

Endurance running is now confined to sport, but Lieberman thinks it gave early
humans an evolutionary edge. Unlike most mammals, or any other primates, we can
run at a reasonable pace for many kilometres, quick enough to keep up with a
trotting horse or dog.

That ability may have allowed early humans to scavenge animal carcasses by getting
to them before animals such as hyenas. "Before the bow and arrow, you?d have a
hard time making a living without running," Lieberman says.

Anthropologist Loring Brace of the University of Michigan, Ann Arbor agrees. He
says that studies of hunter-gatherers show that endurance running to catch prey
is a viable sustenance strategy.


The evidence is clear, we are built for running.
.