As every dog owner knows, teaching Fido to lie down and be calm can be a giant hurdle in obedience class. Now, it turns out that at least among German
Shepherds, genetics play a big role in whether your pet earns a gold star. Researchers gave 104 of the dogs the lie-down-and-be-calm test, and three
other behavioral exams, all designed to assess the dogs' ability to control their impulses. Later, the scientists compared the canines' DNA, looking
specifically at a gene that is connected to the production of dopamine and norepinephrine. These neurotransmitters are involved in our emotional
responses and ability to focus, and have been implicated in humans with attention deficit disorder. The 37
German Shepherds with a shortened version of the gene had the most trouble controlling their impulsive behaviors, regardless of their sex, age, or training. But the dogs with long versions of the gene, such as the one in the photo, passed the impulse-tests with
the calm of Zen master. The study, reported in the current issue of PLoS ONE, may not only help breeders identify hyperactive dogs, but could
prove useful in studies of ADHD in humans.
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