Phylogenetic Independent Contrasts

Phylogenetic Independent Contrasts (PIC) is a comparative statistical method that tests for associations between traits across species while accounting for shared evolutionary history. Developed by Joseph Felsenstein in 1985, PIC solves a fundamental problem in comparative biology: related species share traits due to common ancestry, not independent evolution, which violates the statistical assumption of independence. By comparing trait differences between sister species pairs, PIC removes the confounding effects of phylogenetic relatedness and enables robust evolutionary inferences.