This Week in Research: The Real Paleo Diet; How Parrots Talk

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If you’re considering trying out the paleo diet, why not go all the way? Johns Hopkins researchers have been studying what our pre-human ancestors enjoying snacking on 2 million years ago, and the answer may surprise you.

While it’s easy to picture early humans as relentless hunters who sat around campfires, gnawing on elk legs, the Australopithecus sediba, an ape-like precursor to today’s humans, were vegetarians. “This astonished us,” said Hopkins geochemist Benjamin Passey. “Most hominin species appear to have been pretty good at eating what was around them and available, but sediba seems to have been unusual in that, like present-day chimpanzees, it ignored available savanna foods.” Instead, our pre-human relatives enjoyed a diet exclusively based on forest foods, including fruits and leaves.

Passey used a laser to examine fossilized tooth enamel from sediba specimens, and then used a mass spectrometer to measure carbon levels. High carbon-12 levels indicated a diet made up of mostly forest foods (as opposed to carbon-13 levels, which point to savannah foods, like seeds, roots, and grasses).

“One thing people probably don’t realize is that humans are basically grass eaters,” Passey pointed out. “We eat grass in the form of the grains that we use to make breads, noodles, cereals and beers, and we eat animals that eat grass. In America, we eat animals that are fed corn, and corn is grass, albeit one with an incredible history of human selection. So when did our addiction to grass begin? At what point in our evolutionary history did we start making use of grasses? Eating grasses is a hallmark of humanity, and we are simply trying to find out where in the human chain that begins.”

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Okay, fine, parrots can’t actually talk — at least not in the way that we humans do. But while they can’t spontaneously produce speech like humans, parrots are nature’s best imitators — a whole skill set in itself. And thanks to a new genome-sequencing method, a University of Maryland research team may have helped pinpoint the genes that allow parrots to imitate sounds as varied as human speech, other birds’ songs, and your neighbor’s car alarm.

By pinpointing this particular genetic sequence, scientists may have an easier time understanding how humans’ genetic makeup enables speech development. (And, in my dream world at least, they’ll figure out how to splice this gene into the average house cat, so we can finally have conversations with our pets.) Vocal learning behavior is a key component of learning speech in both humans and parrots, it turns out, and the new technologies allowed researchers to map the regulatory regions of specific genes that contribute to that ability — for example, Erg1, which is a gene that controls the brain’s ability to reorganize itself based on new experiences.

In the best case scenario, one of the study’s author says, the genetic information they’ve found will enable neuroscientists to better understand genetic factors that make people good (or bad!) at communication and speaking well.



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