Wednesday, August 31, 2022

Why you should not trust population genetics or DNA geneology results

Study reveals flaws in popular genetic method (phys.org)

They talk about "PCA" or Principal Component Analysis. This is the method that assumes your data lies in an oval (or an ellipsoid in higher dimensions), assuming the data has "components" that match the axes of the ellipsoid. It is complete nonsense when the data does not happen to lie within an ellipsoid. I had no idea it was used in genetic comparisons but that explains why they keep concluding such absurdities as the "Clovis First" or the uniform populations of South America.

For example:

"Techniques that offer such flexibility encourage bad science and are particularly dangerous in a world where there is intense pressure to publish. If a researcher runs PCA several times, the temptation will always be to select the output that makes the best story," adds Prof. William Amos, from the Univesity of Cambridge, who was not involved in the study.

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