Sir: Your headline "DNA shows how Thor Heyerdahl got it wrong" (8 January) is incorrect. Heyerdahl's theory that humans could sail from South America to Polynesia was confirmed by the successful crossing of the Kon-Tiki raft in 1947.
My DNA studies have shown that a few bones of prehistoric Easter Islanders contain genetic markers that are the same as those of modern Polynesians, supporting the view that Polynesian people reached Easter Island in the past.
But some features of the ancient buildings in Easter Island suggest South American cultural influences. It is clear that the actual physical presence of South American people in Easter Island cannot be ruled out until we have looked at the DNA of a much larger number of archaeological bones of different ages and from different locations in the island. Alas, contrary to what Charles Arthur reports, we have not yet examined a couple of hundred skeletons of the islanders. This will take us years of painstaking research.
Whatever the DNA says, Heyerdahl's claim that people can sail across the Pacific from South America to Polynesia remains undisputed.
Dr ERIKA HAGELBERG
Department of Genetics
University of Cambridge