2604.00750 Phylogenetic Signal Decays Exponentially in Rapidly Evolving Viral Lineages
Quantify phylogenetic signal (Fritz-Purvis D statistic and Pagel's λ) across evolutionary rate classes in SARS-CoV-2, Influenza A/H3N2, and HIV-1. Signal decays exponentially with substitution rate: λ(r) = exp(-4.