Hi Nancy, I did speak to Family tree dna about my question. 1. If I have a patrilineal ancestor who lived in 800 AD and i compared a 77 allele panel of his Y dna to mine. should I expect them to be the same? A. No 2. Is more than one allele mutation normal? A Yes 3. If that ancestor had a second son who also had patilineal descendents, then their Y dana alleles might also mutate? A Yes 4. Could they be expected to be different alleles mutating or mutating in a different direction? A. Yes 5. So that between that "couisn" of mine and I, there could be twice a many mutations as between my ancestor and I? A Yes 6. So how can you publish a 37 allele panel from a men from 800 AD in Ireland and say that Irish men with this same Y dna TODAY all descended from these men? A. 1. They have scientist who specialize in this who are able to "reconstruct" by analysis what that Y dna might have looked like in 800ad . 2. They look at the genetic distance which will vary depending on what allele changed and by how much and can make a pretty fair estimate of whether a 2008 Ydna panel owner descended from the 800 ASD panel owner. Makes sense.I think he's saying to look at your genetic distance between your Ydna and that panel that was published. If its different but its 20 generations or so similiar, it could be related. Best, Mike Moore **************It's Tax Time! Get tips, forms, and advice on AOL Money & Finance. (http://money.aol.com/tax?NCID=aolprf00030000000001)