The f4-ratio: ancestry estimation with one statistic, and when it beats qpAdm
Before qpAdm there was the f4-ratio — one number, two f4-statistics, an ancestry proportion. How the classic estimator works, the famous results built on it, and the precise trade against qpAdm.
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Is qpAdm still reliable? What the criticism established, honestly assessed
qpAdm has been audited harder than any tool in ancient DNA: measured false-discovery rates, resolution floors, protocol failures. What the 2021–2025 criticism literature actually established, what survived it, and how practice changed.
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Dating admixture with DATES and ALDER: when did the mixing happen?
qpAdm says how much; linkage-disequilibrium decay says when. How DATES and ALDER read generation counts out of chromosome fragment lengths, what the dates mean, and how a date corroborates or breaks a qpAdm model.
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qpGraph explained: admixture graphs, find_graphs, and the many-graphs problem
qpAdm's bigger sibling models whole population histories as trees with admixture edges. How qpGraph works, what find_graphs automates, and the 2023 finding that reshaped how graph results should be read.
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