Genes survive for a long time (hence the selfish gene) and modern genetics does not lack in ingenuity or curiosity. Charles Byrne (also known as O’Brien) was an Irishman born in 1761. When he died at the age of 22 he was 7 feet 7 inches (231 cm) tall. His body was bought by John Hunter in 1783 and the skeleton is still in the Hunterian Museum at the Royal College of Surgeons in London. In 1909 Harvey Cushing and the museum's curator, Sir Arthur Keith, opened the skull and found an enlarged pituitary fossa; they concluded that Byrne must have had a pituitary adenoma. A contemporary drawing of Byrne shows him with a pair of very tall twins who were probably related to him. In a current cohort of 140 families with familial isolated pituitary adenoma there are four families from Northern Ireland who each have the same mutation in the aryl hydrocarbon-interacting protein gene (AIP) that predisposes to pituitary adenoma causing gigantism or acromegaly. Now an international team based on the UK has reported having extracted DNA from Byrne's teeth and finding an AIP mutation (New England Journal of Medicine 2011;364:43–50). The same mutation was found in the four families from Northern Ireland. They calculated that Byrne and the Northern Irish families must have shared a common ancestor some 57–66 generations, or 1425–1650 years, …