This is a cool short video that will annoy phrenologists and “race realists”. Analysis of a 12,000+ year old skeleton of a young native American woman, now named Naia, who fell into a cenote and died were initially interpreted to imply evidence of multiple migrations into the Americas — the morphologically distinct shape of her skull was used to suggest that she was not ancestral to modern American Indians, but belonged to a separate branch of the family tree.

I’ve heard similar arguments about Kennewick Man, the 8,000+ year old skeleton found in Washington state. His remains looked “caucusoid,” therefore could not be Native American, and therefore laws that protected native remains did not apply. DNA showed otherwise. It turns out that “looks like” is a poor criterion for assigning genetic relatedness.

Same with Naia. DNA testing showed that she really was related to modern South American natives.

Why was her skull so different from the people she was genetically related to? Scientists once thought that distinctive skull shapes were rigid markers of separate ancestries, implying that robust ancient populations in America, and even Australia and Europe, must be genetically distinct from the populations that came later. But Naia proved that the two population theory was wrong. The dramatic differences in skull shape were not due to different blood lines, but to rapid evolutionary adaptation. Scientists now realize that skull shape is highly plastic and changes based on what we do.

I hope that there is a growing appreciation of the concept of phenotypic plasticity — we are products of both our genes and our environment.