I have been asked to explain several items concerning the DNA numbers now showing up for Jordans. Two of the participants (VA-NC Jordans) have a match to within one number out of 12 (11 of 12 numbers match). Occasionally a gene mutation will take place over the years, so these two people are probably related. They both need to upgrade their markers to 25 to make sure though. When we started with this project, not much was known concerning these DNA tests, but now that the markers are showing up, the questions are starting to be asked. I talked with Ron Lindsay, coordinator of the Lindsay DNA project and asked where the best start would be with understanding DNA. He replied and I'm sending that on to the list. If any of you come up with questions or answers, please send to the Jordan-L list so there will be a record for our future. And please write "DNA" somewhere in the subject line. Thanks. Bob Jordan Greetings Bob, I will attempt to provide you with answers to your questions below. Your question is in bold type, my answer is below it. If a match is 1 off or 10 off -- what really does that mean? If one person has a marker value of 10 and another person has 11 for the same marker, they are a one step or one mutation difference. This does not necessarily mean they are not related at this marker. The simple answer is that there could have been a legitimate mutation over the years. What do the numbers really indicate? The numbers that are reported are the number of repeats of a specific sequence that occur at a given marker. Can we tell nationality trends by looking at the numbers? A certain set of values for a certain set of markers can tell you a particular geographic region that you came from but not necessarily nationality. This is called a modal haplotype such as the Atlantic Modal Haplotype (AMH). Do we have a close match with anyone else in a large data base - other than our family name? This depends on the number of markers you are testing. There have been many instances where "Jones" matched 12 of 12 markers with several other surnames. When you test for 20 or more markers, it is less likely that you will match 21 of 21 markers with someone that you do not share a common ancestor with. Any idea about a web site that can give us a little better idea of how to read the technical issues of these results? My first recommendation and your best bet is to do a few Google searches for the key words you want defined. There is much to be learned from the Internet databases of information on genetics and the human genome project. One of the best sites to read is the National Institute of Standards and Technology web site at http://www.cstl.nist.gov/div831/strbase/index.htm . Also the Genomics Primers at http://www.ornl.gov/hgmis/publicat/primer/intro.html and http://www.dnaftb.org/dnaftb/ . Also check out the Y-STR Haplotype Reference Database at http://ystr.charite.de/index_mkl.html . I would also recommend that you subscribe to the Genealogy-DNA List because many of the subscribers are asking the same questions you are asking and there is always someone with an answer. Bob, I am sure I have only touched the surface with your questions and I do not claim to be an expert on this subject. There is much that can be learned but it takes a lot of time and effort to absorb just enough to be dangerous. Good luck with your Jordan Project. It is indeed tough to get people interested in participating but my bet it will get easier as the database grows and people start to see that they might match up with another published Lindsay or Jordan lineage. Ron Lindsay San Jose, CA