Science roundup: Starchy genes

Per Carl Zimmer, not only did the invention of fiber allow for the roasting of tubers and later, the roasting or baking of grains, as well as roasting meat, but a bit of evolution gave humans genes to create the enzyme amylase to break down starches.

That evolution came in two waves, actually, he says.

One was about the time generally guesstimated for the domestication of fire, and would of course spread globally as that was long before the exodus of modern Homo sapiens from Africa.

The other? About 12,000 years ago. That's before humans in Southwest Asia became sedentary farmers, but, it's right about at the time that they moved from pure hunter-gatherers to more of "multiple strategies" on their food, including more work on semi-domesticating wild grains. (We know bread was being baked and even toasted before this time.)

But wait, that's not all. Here's the tie to modern times and refined starches:

As ancient societies developed different diets, the new research suggests, they evolved to have different numbers of amylase genes. Dr. [Omer] Gokcumen speculated that people today who have fewer amylase genes may be more vulnerable to diseases like diabetes that are fueled by a starch-heavy modern diet. Down the line, the findings could point to potential amylase-based treatments for these diseases.

There you go.

The reason we know that the initial evolution was likely long ago is indirect, but smart. Neanderthals, we can tell, had also evolved extra genes for amylase creation. Peter Sudmant offered further correlation for the evolutionary timeline, but cautioned against trying to directly connect it to the domestication of fire at this time.

But wait, that's not all.

This new genetic information also has these scientists rethinking the role of amylase. They say that it may as much or more be for signaling the digestive and energy-distribution systems of the body in general that food is on the way, vs. being specific for starch digestion.

Thinking beyond the story, might this be a partial explainer for why many American Indians have such problems with diabetes? (Another partial explainer would be food deserts, as with African Americans.) Obviously, the second evolutionary round would have been after the first Amerinds entered the Americas, but the first evolutionary round could have had a small ingroup with fewer genes.