The researchers acknowledged that a mitochondrial haplogroup result, while strongly suggestive, was not as definitive as a full nuclear genome analysis would be.

They acknowledged that the specific mechanisms of morphological change over time were not established by their data.

And they acknowledged that the interpretation they offered was one model among several that the data was consistent with.

This kind of intellectual honesty — stating findings precisely, acknowledging limitations, distinguishing what the data shows from what the data implies — is what distinguishes solid scientific work from the kind of overconfident claim-making that has sometimes characterized debates about early American populations.

The Hoyo Negro paper earned the response it received partly because it was careful in exactly the ways that some earlier contributions to this debate had not been.