The assessment is probabilistic, not deterministic.

The genetic variants associated with skin color are statistical predictors — variants that are more common in people with darker or lighter skin, but not exclusively present in one group or the other.

A pigmentation prediction based on genetic variants is a best estimate, not a certainty, and the researchers involved in the Cheddar Man study were careful to emphasize this point.

Their assessment that Cheddar Man had dark to black skin was based on the combination of genetic variants in his genome compared to the patterns established in living populations.