For eye color, the analysis suggested blue or blue-green eyes — a prediction that was, if anything, more robust than the skin color result, because the genetic basis of eye color, particularly the blue-brown distinction, is better characterized and depends more heavily on a smaller number of high-effect variants. Hair color and texture were predicted as dark, probably curly.
The combination — dark skin, blue or blue-green eyes, dark curly hair — was the finding that generated headlines around the world in February 2018. It contradicted the assumptions embedded in the 1998 Manchester reconstruction and it challenged popular intuitions about what “ancient Europeans” looked like.
But what did the result actually mean, and how confident could researchers be?
—
## Reading the Uncertainty: What “Suggested” Really Means
The headline for this article uses the word “suggested.” That word is precise, and understanding why it is precise requires understanding what genetic phenotype prediction can and cannot establish.
Dark skin, blue or blue-green eyes, and dark curly hair represent Cheddar Man’s most probable profile given the genetic variants recovered from his remains. They do not represent a photographed or observed fact. They do not mean that researchers have determined his exact skin tone. They do not mean that every individual with his genetic profile would look identical.
Susan Walsh, whose forensic phenotyping tools were used in the analysis, was quoted by New Scientist in March 2018 as saying: “It’s not a simple statement of ‘this person was dark-skinned.'” She described the result as his “most probable profile, based on current research.” She noted that DNA can degrade over ten thousand years in ways that might affect the results, and that other parts of the genome — variants not captured by the current predictive models — could influence skin color in ways not accounted for.