Peter, Thank you so much for this post it was very helpful to me. I have a mutation in my DNA and did not understand it. It made me fell lesser of a Kincaid but now I can see that there was only a change in one stran of my DNA. This note would be useful for many others like me. Thanks, Toney Kincaid - 33001 ----- Original Message ----- From: "Peter A. Kincaid" <7kincaid@nb.sympatico.ca> To: <kincaid@rootsweb.com> Sent: Friday, October 17, 2008 8:38 PM Subject: Re: [KINCAID] DNA Question > Hi Kelly, > > The following is something I put together a few years ago > for my DNA web page. Perhaps this will help with the > basics a bit. > > Everyone of us contain structures called chromosomes. These chromosomes > usually come in pairs, one inherited from the mother and one from the > father, and humans have 23 pairs of chromosomes altogether. In 22 of the > 23 pairs, the 2 chromosomes are very similar. However, the 23rd pair is > made up of two possible combinations of 2 very different chromosomes, the > X and the Y chromosomes. All of us have at least one X chromosome, which > we have inherited from our mother. The second chromosome in this pair is > always inherited from the father. If it is another X chomosome then the > pair readily mixes and the embryo developes into a female. If the second > chromosome inherited from the father is a Y chromosome then the embryo > developes into a male. Since a male's 23rd pair are disimilar (X & Y), > genetic material cannot readily exchange between them. The result is that > the Y chromosome of every living man contains portions that directly > resembles that of his father, grandfather, great gra! > ndfather etc. and cousins of any degree who also have the same male > ancestor. > > The Y chromosone is about 60,000,000 base pairs long. One base on the DNA > strand can be one of the following four nitrogen containing chemicals: A > (adenine), T (thymine), C (cytosine) and G (guanine). There are two > strands in the DNA chain parallel to each other and connected. They are > connected because Adenine (A) pairs with thymine (T) and cytosine (C) > pairs with guanine (G). Thus, if you have a A on one strand then its > opposite strand will have a T so they can join. > > When the DNA within the male Y chromosome is copied from generation to > generation, small mistakes are occasionally made. These mistakes give rise > to differences between Y chromosomes of two individuals called > "polymorphisms". An person's combination of polymorphisms identifies a > unique sequence or "haplotype" with which to make comparisons to that of > another individual. > > STRs (abbreviation for Short Tandem Repeats) are sections of DNA where a > short pattern (2-5 bases) has been identified as repeating a certain > number of times in a row (in tandem). DYS391 is an identified STR with the > 'GATA' pattern repeating at one specific location (repeating patterns at > specific points are called markers). For many Kincaids in our project it > has been determined that the DYS391 marker repeated 12 times. In that > section of the Y-DNA one strand of the DNA looks like: > > GATAGATAGATAGATAGATAGATAGATAGATAGATAGATAGATAGATA. > > For other Kincaids in the project there was a mutation in one of the GATA > pairs (ie. perhaps a G became a C) resulting in only 11 GATA repeats being > counted for the same marker instead of 12 (ie. a mutation is when the > number of repeats increases or decreases by one or occasionally two or > more). Since we are dealing with more than one base pair (ie. one letter) > then mutations can be observed frequently enough in STR markers to be of > use for genealogy. > > Peter A. Kincaid > Fredericton, NB, Canada > > ----- Original Message ----- > From: lewisjo@junct.com > To: KINCAID@rootsweb.com > Sent: Friday, October 17, 2008 3:28 PM > Subject: [KINCAID] DNA Question > > > Can anyone tell me what the markers mean? Each one has a value, but what > is the orginal meaning of the marker, does it, in itself mean anything > that we can understand? When you say "mutations", do you mean that it is > just a different value than the rest of the group has? Isn't there > anything significant about that particular mutation at that particular > marker? > Kelly > > To see the Kincaid of all spellings DNA chart in Excel: > http://freepages.genealogy.rootsweb.com/~adgedge/Research/April%202004/Kincaid%20%20DNA.xls > > > ------------------------------- > To unsubscribe from the list, please send an email to > KINCAID-request@rootsweb.com with the word 'unsubscribe' without the > quotes in the subject and the body of the message