SNIPPETS
Horse gaits controlled by
genetic mutation spread by
humans
From the Faroe Pony to the Spanish Mustang, fewer
animals have played such a central role in human
history as the horse. New research in Animal Genetics
reveals that a horse’s gait, an attribute central to its
importance to humans, is influenced by a genetic
mutation, spread by humans across the world.
The team, led by Dr. Leif Andersson from the Swedish
University of Agricultural Sciences, explored the
distribution of a mutation in the DMRT3 gene which
affects the gait of horses, known as the ‘gait keeper.’
“All over the world, horses have been used for
everyday transportation, in military settings, cattle
herding and agricultural power, pulling carriages and
carts, pleasure riding or racing,” said Dr. Andersson.
“Over the centuries, horse populations and breeds
have been shaped by humans based on the different
purposes for which the animals were used.”
The DMRT3 gene is central to the utility of horses to
humans, as it controls a range of gaits as well as pace.
From racing to pleasure riding, many species have
been bred to encourage smoothness of gait.
“For example, the Paso Fino is a breed from Latin
America in which the frequency of the ‘gait keeper’
mutation is nearly 100%. It is claimed that the Paso
Fino gait is so smooth that you can have a glass of
wine in your hand without letting it spill,” said Dr.
Andersson.
The team analyzed 4,396 horses from 141 breeds
around the world and found that the ‘gait keeper’
mutation is spread across Eurasia from Japan in the
East, to the British Isles in West, on Iceland, in both
South and North America, and also in breeds from
South Africa.
“Humans have spread this mutation across the world
primarily because horses carrying this mutation are
able to provide a very smooth ride, in some breeds
referred to as a running walk,” said Dr. Andersson.
“During such ambling gaits the horse has at least
one foot on the ground that means that the vertical
movement of the rider is minimal.”
Human and dog brains both have
dedicated ‘voice areas’
The first study to compare brain function between
humans and any nonprimate animal shows that dogs
have dedicated voice areas in their brains, just as
10
people do. Dog brains, like those of people, are also
sensitive to acoustic cues of emotion, according to
a study in the Cell Press journal Current Biology on
February 20.
The findings suggest that voice areas evolved at least
100 million years ago, the age of the last common
ancestor of humans and dogs, the researchers
say. It also offers new insight into humans’ unique
connection with our best friends in the animal
kingdom and helps to explain the behavioral and
neural mechanisms that made this alliance so
effective for tens of thousands of years.
“Dogs and humans share a similar social environment,”
says Attila Andics of MTA-ELTE Comparative Ethology
Research Group in Hungary. “Our findings suggest
that they also use similar brain mechanisms to
process social information. This may support the
successfulness of vocal communication between the
two species.”
Andics and his colleagues trained 11 dogs to lay
motionless in an fMRI brain scanner. That made it
possible to run the same neuroimaging experiment
on both dog and human participants -- something
that had never been done before. They captured
both dogs’ and humans’ brain activities while the
subjects listened to nearly 200 dog and human
sounds, ranging from whining or crying to playful
barking or laughing. The images show that dog and
human brains include voice areas in similar locations.
Not surprisingly, the voice area of dogs responds
more strongly to other dogs while that of humans
responds more strongly to other humans.
The researchers also noted striking similarities
in the ways the dog and human brains process
emotionally loaded sounds. In both species, an
area near the primary auditory cortex lit up more
with happy sounds than unhappy ones. Andics says
the researchers were most struck by the common
response to emotion across species.
There were some differences, too: in dogs, 48% of all
sound-sensitive brain regions respond more strongly
to sounds other than voices. That’s in contrast to
humans, in which only 3% of sound-sensitive brain
regions show greater response to nonvocal versus
vocal sounds.
The study is the first step toward understanding how
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