The Broader Science Of Pigmentation Evolution

To fully appreciate why the Cheddar Man finding matters, it helps to understand the broader scientific debate about when and how light pigmentation evolved in Europe — a debate that ancient DNA evidence has substantially clarified.

Before ancient DNA provided direct evidence, researchers estimated the timing of light pigmentation evolution in Europeans from indirect evidence.

They looked at the distribution of pigmentation variants in modern populations, used population genetic models to estimate how long it would take selection to drive those variants to their current frequencies, and tried to infer the timeline.

One approach used the genetic diversity around pigmentation-related genes as a signal of selection: genes that have been strongly selected show reduced diversity in the genomic region around the selected variant (a signature called a “selective sweep”).