Re: Duplicate genes help humans dive deep distances

Marc Verhaegen wrote:

A good illustration of the usual savanna biases: genes that "transport water
& sugar into cells" are interpreted as proving enducrance running... Can
you believe?? Equally stupid would be: genes that transport sugar+water
prove diving.

Serious genetic evidence OTOH:

1) Humans have lots of olfactory genes inactivated as compared to chimps:
this is difficult to understand in a savanna milieu, but is simply expected
in diving lifestyle.

2) Humans have inactivated masticatory musculature (MYH 16) as compared to
chimps: equally impossible to understand in a savanna milieu, but to be
expected when soft food was important.

good examples of the aat bias - bla bla on something totally unrelated.


Op 31-07-2007 03:58, in artikel 46AE972D.2BC00B32@xxxxxxxxxxxxxxx, Rich
Travsky <traRvEsky@xxxxxxxxxxxxxxx> schreef:


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-runn
ers.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, you¹d 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.
.