| Interpreting Your Results | FamilyTreeDNA's discussion-read here first |
| Haplotypes | The genealogical testing companies use more
rapidly changing markers called STRs (Short Tandem Repeats), and your
haplotype is the complete set of results on whatever markers were tested.
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| What are Haplogroups? | Haplogroups are very broad categories.. They
are comprised of haplotypes in groups showing Allele (the DYS # markers)
Information. The founding father who had the mutation which defined a
haplogroup had a specific haplotype. His descendants will accumulate
mutations on that foundation, and after hundreds or thousands of years,
there will be a great diversity of haplotypes, but there will still be some
traces of the founding father.
A good rule of thumb for determining haplogroup is the following:
The members of HG1 are thought to be the descendants of the Paleolithic hunter-gatherers who arrived in Europe before the last Ice Age about 40,000 years ago (Aurignacian culture). That pattern is most common in Western Europe, but is also found in all other parts of Europe. The members of HG2 are believed to be the descendants of two later waves of humans into Europe. The last of these waves arrived about 8,000 years ago and is credited with introducing agriculture into Europe. HG2 is most common in Southern and Central Europe, but that haplogroup is also often seen in those of Anglo-Saxon and Scandinavian descent. The haplogroup HG3 is seen more frequently on the eastern side of Europe (9% of the population of Turkey is HG3). But HG3 is also common in Scandinavia, and is said by some to be indicative of "Viking blood" when seen in paternal lines originating in the British Isles. The forefather of all HG3's is thought to have been born in the Ukraine during the last Ice Age about 15,000 years ago. Keep in mind that haplogroup classification is fairly useless for locating the place of origin of your paternal line. While each haplogroup has general areas in which it is more common, there has been enough mixing of people on the European continent to prevent using these classifications to pinpoint any single place of origin. There will be exceptions to the above rules - but this method works well for most men whose paternal line is of Western or Central European descent. The importance of haplogroups for genealogists lies in the fact that you will share many marker values with anyone else who belongs to the same haplogroup. For more reading see http://freepages.genealogy.rootsweb.com/~dgarvey/DNA/RelGen/6markers.html |
| MUTATIONS | How often do mutations occur? They can and do
occur at any point in time. For a set of 12 markers, they occur at an
AVERAGE rate of about one every thousand years in a given line of descent.
What about 2 Step Mutations- The vast majority of the time,
mutations appear to be "one-step" -- that is, the number of repeats
increases or decreases by one. If you see a difference of two repeats at one
locus, the question becomes whether there was a one-step mutation in some
generation, then another one-step mutation at the same locus in later
generations (two one-step mutations), or whether there was a jump of two
(one two-step mutation). It's impossible to tell after the fact, but
two-step mutations have been observed in father-son pairs. Bruce Walsh, the
population geneticist who consults with FTDNA, has some details on how
to handle this statistically, with tables for two one-step mutations vs one
two-step mutation:
http://nitro.biosci.arizona.edu/ftdna/TMRCA.html See Mumma Family
Example for Discussion of Mutations from Known Ancestors -
http://www.mumma.org/DNA.htm |
| Fast Moving Markers | #464, 449, 439-Markers mutate at different rates .FamilyTreeDNA's
discussion.
Basically, fast moving markers, if other markers, particularly on 25, match, can highlight the branch similarities through a given line of descent from a common ancestor. |
| Understanding Your Results: Are We Related? | Some Family Tree DNA customers will
have Y DNA 12 Marker Exact matches with other surnames, and on a rare
occasion, a 25 Marker Exact match with another surname. Most likely these
people are not related in a genealogical time frame. To understand how this situation occurs, we start by looking at the population before the origin of Surnames. Before the adoption of Surnames, there existed various Y DNA 12 Marker and 25 Marker results in the male population. The quantity of persons with any particular Y DNA result varied, based on their success of having male children, the survival of the male children, and how many of the male children procreated more male children. There was also migrations throughout the world. In addition, during this time, Markers continued to mutate, just as they do today. Surnames began to be introduced and adopted at different rates in different countries, typically with the upper classes adopting surnames initially. Different persons through out a region of the world population would have had the same 12 Marker result at the time of the introduction of surnames. This situation would have occurred due to some of the people being related and the others as a result of Convergence. For more information on Convergence, see the Facts and Genes Vol. 1, Issue 5, the article titled "Haplotypes: Convergence". http://www.familytreedna.com/facts_genes.asp?act=show&nk=1.5As the adoption of surnames occurred, different persons with the same 12 Marker result most likely adopted different surnames. For example, perhaps there was a person in London who adopted the surname Barker and another person existed in Scotland with the same 12 Marker result, and they adopted the surname MacGregor. Assuming that there were no mutations, the descendents today would have a 12 Marker exact match, but they are not related in a genealogical time frame. The key element in evaluating 12/12 Matches and 25/25 matches is the time frame. We are all related at one point in time. For our family history research, we are most likely only interested in a genealogical time frame. The genealogical time frame most likely does not start before the adoption of surnames, so the first requirement to determine relatedness is the surname. The Marker mutation rate does not care about surnames, or whether the person even had a surname. Markers mutated before surnames and after the adoption of surnames. By utilizing the criteria of surnames, you are establishing the time frame for evaluating relatedness. If two people match 12/12 or 25/25 and the surname matches or is a variant, then they are probably related since the time of the adoption of the surname. If two people match 12/12 or 25/25, and the surname does not match, they are most likely related before the adoption of surnames. (This statement excludes adoption, and extra marital events.) Being related before the adoption of surnames is probably not relevant to those doing family history research, so matches with others of different surnames are ignored. When two people match and share the same surname, they would be related since the time of the adoption of the surname. Scientifically, the probability that two people are related is the same on a 12 Marker match and a 25 Marker match, 99% probability that they are related. The question then becomes WHEN the relatedness occurred. A 25 Marker match has a smaller window of 1200 years, while the 12 Marker match has a much larger window of 2500 years. The surname effects the time frame for when they are related. When the surname matches, the time frame is shortened, so the two people are related since the adoption of the surname. From a genealogical perspective, determining the first recorded instance of the surname would put a time frame for the adoption of the surname, even though it could have been used prior to that even, but not recorded or the documents lost or destroyed. Matches with other surnames can occur for anyone, with any 12 Marker or 25 Marker result, who belong to any Haplogroup. We happen to observe this situation occurring more frequently with those who belong to Haplogroup R1b, since this Haplogroup comprises a large percentage of the European population and their descendents. Most matches with other surnames are not worth investigating. 12 Marker results, called Haplotypes, began evolving and mutating with the first Humans. The time frame for relatedness is a relevant factor, and surnames establish a time frame. |
| How many mutations to expect? | http://www.roperld.com/YMarkersProbabilities.htm |
| Interpreting Genetic Distance | PER
FAMILY TREE DNA Interpreting Genetic Distance
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