""We think that selection is strongly favouring more copies in populations
with more starch in the diet," says Dominy. The study is one of the first
to show that natural selection can lead to an increase in gene copy
numbers.

If that increase coincided with the dramatic expansion in our ancestor's
brain size about 1.8 million years ago, that would be the strongest
possible evidence that roots and tubers, not meat, fuelled our
intelligence."

Very good, some science at last instead of quibbling. Given the potential
confounding factors of knowing back 1.8 million years the same authors
mentioned, how do we know this is any different?

Science proceeds by alternative models over time sorting and sifting until
a concensus is reached. Where does the above stand today in that
concensus?

Speaking of enzymes, we know that even within a few thousand previous
years
adaptations to local foods and changes in diet have caused the genetic
source for them to be toggled on and off and to be replaced. How do we
know
what they observe about one related to digestion of starch is not in fact
a
reflection in the past 10 thousand years of a shift to more grain and
other
intensely starch rich diets?

Speaking also of enzymes, what is the specific function of elastase in the
human metabolism and how does it relate to changes in human diet?