We are naturally selected to be drunks, and …
|December 3, 2014||Posted by News under Natural selection, News|
Study shows pre-human ancestors adapted to metabolize ethanol long before humans learned about fermentation
Humans have been consuming beverages that make them tipsy, drunk and/or sick for a very long time, of that there is little doubt. But why do we have the ability to metabolize ethanol in the first place? That’s what the team set out to answer. They began by sequencing an enzyme called ADH4—it’s what’s responsible for allowing us to metabolize ethanol. Other primates have it as well, but not all metabolize ethanol as well as we do. By sequencing ADH4 found in a 28 mammal species including 17 that were primates, the team was able to create a family tree of sorts based on ethanol metabolizing ability. The team then tested those sequences for their metabolizing ability by synthesizing nine kinds of the ADH4 enzyme. Doing so showed the researchers that most early primates had very little ability to metabolize ethanol for most of their early history.
Then, about 10 million years ago, some of the ancestors of modern humans suddenly were able to do a much better job of it, while others that diverged and led to apes such as orangutans, did not. This discovery led the team to wonder what might have occurred to cause this to come about. They note that other evidence has shown that around this same time, the planet cooled slightly, making life a little more difficult for our tree dwelling ancestors. They suggest they began climbing down out of the trees to eat the fruit that fell, which gave them a food advantage and a reason for developing the ability to metabolize ethanol—otherwise they would have become too drunk from eating the fermenting fruit to defend themselves or live otherwise normal lives. If true, the theory would also offer a major clue as to why our ancestors became terrestrial.
And it isn’t even April 1. Hmmm.
If this story means a lot to you, phone Alcoholics Anonymous.
For our other excellent readers, please note, News blogging will be light today until the News desk finishes up at a day job.
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Hat tip: Timothy Kershner