Abigail That is a great piece of writing. The thing that bothers me a little bit is the statement that is the copies get fuzzy. Each marker on average changes 1 time every 500 generations and that make a fuzzy clock if you know how to make the calculation. When test at Y67 it not too fuzzy in a couple of years there will be a Y100 test and that will be even less fuzzy. john B. project software any volunteers http://www.dna-pat.com/ http://archiver.rootsweb.com/th/read/genealogy-dna/2007-02/1172410771 http://forums.dna-pat.com/index.php ============================================================= I thought that some of you on the BRYANT list would benefit / enjoy reading the basics regarding DNA testing. This came from my ROBINSON list and I felt it was worth the read. Somehow simplifies some of it. Abigail ----- Original Message ----- From: "Don Drake" <dondrake@surfnetnc.com> To: <robinson@rootsweb.com> Sent: Wednesday, April 25, 2007 10:59 PM Subject: Re: [ROBINSON] Sam's Question >I spent some time today sorting out the Robinson DNA page placing the > results within matching subgroups. Hopefully, that will make it easier > to see who is related and who is not. > > First, a little DNA basics. You may remember from high school that > every cell in our bodies (except for the red blood cells) contains our > individual DNA fingerprint. The DNA is contained in the Mitochondria, > which are located in the cell body and in the X and Y chromosomes found > in the cell's nucleus. When a baby is conceived, the child receives one > chromosome from each parent; an X chromosome from the mother and either > an X or Y from the father. The father's contribution determines the > child's gender; the Y chromosome results in a male child and an X > chromosome results in a female child. The Mitochondria are past from the > mother to each of her children. There are two types of DNA projects > available to genealogists: a Y-DNA project or a MtDNA (mitochondrial) > Project. Because the Y chromosome is passed only from father to son, > participants in a Y-DNA project must be male and the project examines > the ancestry of the direct male line. Conversely, the participants in a > MtDNA project may be either male or female and, since males do not pass > Mitochondria on to any of their children, these projects examine the > mother's ancestry following her direct female line. > > Every time a male child is born, a copy of the father's Y chromosome is > passed along. Now imagine that you make a copy of a photograph on a > copy machine and then you make a copy of the copy, instead of using the > original to make the second. The second copy will not be as clear as > either the original or the first copy. If you keep making copies of the > copies, eventually, the result will become very fuzzy. The same thing > happens with the Y chromosome. > A man's DNA contains Alleles or "markers." Over time, these markers > begin to mutate. Thousands of years ago, when the early humans began to > migrate to different parts of the world, they formed isolated population > groups, (Haplo Groups). As new generations were born, the Y chromosome > began to mutate, but the different populations mutated on different > markers. Today, when we look at a man's DNA, we can tell where his > earlier ancestors came from (his Haplo Group) by looking to see which > markers mutated. > > Each DNA marker is made up of repeating sequences of acids and other > stuff that . . . well I don't know what they are. But they repeat. You > count how many times they repeat and that's the value for that marker. > When you look at someone's DNA result, you will see a group of up to 67 > one and two-digit numbers. The numbers don't mean that much by > themselves. Well, not to me anyway. But when we compare two tests, > that tells us a lot about the two donors. We can determine how likely > it is they share a recent common ancestor (recent being since 1000 A.D.) > and when that ancestor likely lived. > > So, to get a DNA signature for Rev. John Robinson's family, we don't > need to take Rev. John's DNA, we simply need to take a sample from his > living, direct line, male, descendants. If we find two living males, > surnamed Robinson, who can show a paper trail following a direct, > unbroken, male line (no females in the line) back to Rev. John Robinson, > we would expect their Y-DNA results to be exact matches. If they are > not exact matches and they are off by more than one or two mutations, > then more than likely, one of them has made a mistake in his research or > there may have been an adoption or a non-paternal event (politically > correct way of saying that someone had an affair). > > Currently, FamilyTreeDNA offers DNA products of 12, 25, 37 and 67 > markers. The higher the marker, the greater our confidence that an > exact match will correctly predict a recent common ancestor. For > instance if two individuals match on 12 out of 12 markers, then they > have a 55% chance of sharing a common ancestor within the past 8 > generations (by the fifth great grandfather). For a 25/25 match that > probability is 85%, a 37/37 match is 97% and a 67/67 match is 100%. > > I hope this helps. > > Don > > sam kelly wrote: >> Don, >> Good info but I am am absolute ignorant when it comes to these lists. >> Could you please tell me if ALL these Robinsons are related then?? sam >> >> Don Drake <dondrake@surfnetnc.com> wrote: >> I just uploaded ancestor charts for the donors of Kit Numbers 82612: >> EKA >> Thomas Robinson b.c. 1803 in England and N31651: EKA, John Robinson who >> arrived in Chester, PA on the Bristol Merchant in September of 1685 with >> his wife, Katherine. >> >> Please check them out. Again, if there are any donors on the list who >> haven't gotten me their EKAs, please do so. >> >> Thanks again, >> Don >> > > > -- > > Donald E. Drake > > Moyock, NC > > http://freepages.genealogy.rootsweb.com/~drakerobinson/index.htm > > > > ------------------------------- > To unsubscribe from the list, please send an email to > ROBINSON-request@rootsweb.com with the word 'unsubscribe' without the > quotes in the subject and the body of the message > ------------------------------- To unsubscribe from the list, please send an email to BRYANT-request@rootsweb.com with the word 'unsubscribe' without the quotes in the subject and the body of the message