I might add that while I have been very fortunate in finding Y-DNA matches for myself, our daughter's son matches no one, even at 12 markers. - a real wild card... Also, exceptions can always be made/found for what I've written below, but for most everyone the 67-markers test is the test to go with. Cliff. Johnston "May the best you've ever seen, Be the worst you'll ever see;" from A Scots Toast by Allan Ramsay ----- Original Message ----- From: "Cliff. Johnston" <moments-in-time@comcast.net> To: <countycork@rootsweb.com>; <CountyCork-L@rootsweb.com> Sent: Tuesday, August 25, 2009 10:17 AM Subject: Re: [CO CORK] DNA question > Pat, > > Both sons carry your father's Y-DNA; accordingly, unless the male line > has > been interupted, they will also have the same Y-DNA as your great > grandfather. Unfortunately there is no way to connect back to your great > grandfather other than a paper trail. Y-DNA testing will only show > relationships between people who have been tested for their Y-DNA. One > could get a Y-DNA sample of one's great grandfather if one knew where he > was > buried, but most people do not go this route unless the circumstances are > extra-ordinary. Of course this means that Y-DNA can and is being used by > 10's of thousands of people to find what I refer to as "Y-DNA Cousins". > Now > here is where the science meets statistics meets art. How close 2 or more > Y-DNA Cousins are to each other when they have no known paper trail is a > wee > bit of a SWAG. > > For most people considering taking the Y-DNA test let me recommend > strongly > the 67-markers test. Why? Experience with my Johnstons in Poldean group > has taught me that. Let's take a look at the various tests and what we > can > learn from them. > > 12-markers test: the most basic test being marketed; used by National > Geographic in their human genome project in an attempt to explain the > migration of mankind from his inception to today. If one is lucky, one > will > find out which major haplogroup one belongs to and little else - many do > not > though. > > 25-markers test: a waste of time and money, in my opinion. It adds > little > that is really useful to the 12-markers test. > > 37-markers test: this test helps in defining close relationships within > the > past few hundred years. For example, in our Johnstons in Poldean group > we've been able to help 2 pairs of Cousins to get together and > cooperatively > work in finding their Most Recent Common Ancestor. Both pairs had a > difference of only 1 mutation, but their MRCAs were from different > generations, ie: one pair found their MRCA in the 1750's while the other > pair found their MRCA in the 1850's. On the other hand one of our Cousins > had 2 of his grandsons tested. Each differed by 1 mutation from his > results, and each was at a different locus (marker). All of this > illustrates the well-known fact that mutations occur randomly. We never > know when they will happen or where. > > 67-markers test: in most cases, other than when 2 or more Cousins are > known > to be from the same family line, this is the test that should be taken. > The > loci, or markers, #38-67 are most useful in determining direct family > lines. > For a year or so in our Johnstons in Poldean group we relied primarily on > the 37-markers tests, but when a handful of Cousins had their tests > upgraded > to 67 markers it became evident that the upgrade was invaluable as it > indicated a close relationship between 2 Cousins who thought that they > were > from different family lines, and 2 other Cousins who thought they were > from > the same family line turned out to be from totally different lines. Now > that we've had 33 of our Cousins upgrade to 67-markers we are "true > believers" in getting the 67-markers test done first. > > I hope that this helps you a wee bit :-) > > Good hunting, > > Cliff. Johnston > "May the best you've ever seen, > Be the worst you'll ever see;" > from A Scots Toast by Allan Ramsay > ----- Original Message ----- > From: "pat lewis" <carmodyp@bellsouth.net> > To: <CountyCork-L@rootsweb.com> > Sent: Monday, August 24, 2009 10:41 PM > Subject: [CO CORK] DNA question > > >>I have no living male members except my sons, Father died in 1966 , >> brother in 1987........... Could either son have the DNA test and what >> would it show, how could I make any connection to great grandfather who >> died 1905 or any living relative that I know nothing about? >> Check out the Ireland GenWeb County Cork Website at: >> http://www.rootsweb.com/~irlcor/ >> It is a good place to find information related to your family research. >> ------------------------------- >> To unsubscribe from the list, please send an email to >> COUNTYCORK-request@rootsweb.com with the word 'unsubscribe' without the >> quotes in the subject and the body of the message > > Check out the Ireland GenWeb County Cork Website at: > http://www.rootsweb.com/~irlcor/ > It is a good place to find information related to your family research. > ------------------------------- > To unsubscribe from the list, please send an email to > COUNTYCORK-request@rootsweb.com with the word 'unsubscribe' without the > quotes in the subject and the body of the message