Non-paternal events (NPEs) are a significant factor to be aware of in all Y-DNA studies. I have recently done some practical analysis of their incidence in the Manx Y-DNA project which may be helpful to others – see http://wp.me/p2AJd2-88 cheers John John A Creer Home Email Address           john@creer.co.uk (alternatives creer@one-name.org or jacreer@gmail.com ) Family History Websites      www.ballacreer.com www.manxdna.co.uk www.creer.co.uk