Y-DNA Tests

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If you are interested in DNA testing of other people that are of the I haplogroup, go to the Clearing House for Leigh/Lee Lines of the I-Haplogroup. That blog explains the results given by the two companies we are using for our testing of descendants of our ancestor, Ralph Leigh. This information is necessary for one to understand and interpret correctly the actual data returned from the testing.  Be aware, though, that the data in that blog are several years old. The companies that we are using for DNA testing are FamilyTree-DNA and DNA-Ancestry.

FamilyTree-DNA

FamilyTree is closely coupled with geneticists at the University of Arizona and other universities. The choice of markers to be tested, the testing procedure, and the interpretation of the results obtained are based on recommendations from these scientists.

After completing Y-DNA testing of a person, FamilyTree returns the following information.

Marker Values

A certificate certifying that the person had their Y-DNA tested and giving the values of the markers is given to the person who was tested. In addition, FamilyTree has a website, called ysearch.org, that can be used by anyone to perform comparisons of the markers with the markers from other persons tested by FamilyTree. Persons who have been tested are encouraged to but not required to submit their markers and values to ysearch.

Genetic Distance and Likelihood of a Relationship

The scientists associated with FamilyTree developed recommendations whether or not two people who have exact or close matches in their markers are related. These recommendations are relative to the number of markers involved in the testing and the Genetic Distance between the two people. Here are links to the recommendations. As you read the recommendations, you will notice that the scientists assumed the two people have a common surname. This is the usual case, but it may not be the case if the common ancestor lived before the adoption of surnames or if that ancestor was an adopted or illegitimate child. Even if the two people have different surnames, the recommendations are still valid for them, since a change in a surname does not change the genetic relationship between them. The recommendations are the basis for our acceptance or not of a relationship between the two people.

Haplogroup

The name of the person's Haplogroup.  For an additional cost, Family Tree will perform a Deep Clade test on the DNA to obtain a greater resolution on the person's Haplogroup.

The probabilities of the TMRCA to a common ancestor, for matches identified by FamilyTree and reported to the persons who were tested. These probabilities are based on technical information from the scientists associated with FamilyTree, and the probabilities take into account the random and volatile nature of the marker values.

For results imported into Ysearch from other testing companies, the following table can be used to yield the probabilities of when the common ancestor likely lived. In some cases, the values in the table are rounded to whole numbers. A note should be made that tests results from other companies may have to be modified before they are imported into Ysearch.

Number of matching markers	50% probability that the MRCA was no longer than this number of generations	90% probability that the MRCA was no longer than this number of generations	95% probability that the MRCA was no longer than this number of generations
10 of 12	16	56	72
11 of 12	17	39	47
12 of 12	7	23	29
23 of 25	11	23	27
24 of 25	7	16	20
25 of 25	3	10	13
33 of 37	11	19	22
34 of 37	6	12	15
35 of 37	6	12	14
36 of 37	4	8	10
37 of 37	2 to 3	5	7
62 of 67	7	12	15
64 of 67	6	12	14
65 of 67	6	12	14
66 of 67	4	8	9
67 of 67	2	4	6

Contact Information

The name and email address of the contact person for the testing. The contact person doesn't have to be the person providing the DNA sample.

DNA-Ancestry 

DNA Ancestry partners with Sorenson Genomics to analyze the DNA samples that are submitted. Sorensen has a modern DNA lab that uses state of the art techniques to analyze the samples.

After completing the Y-DNA testing of a person, Ancestry returns the following information.

Marker Values

When the contact person logs into his or her account and clicks the DNA button, they are taken to their My DNA Console where they can view their test results (marker values) and find paternal matches. A pdf file containing the marker values can be downloaded.

Haplogroup

The name of the person's Haplogroup. Running a separate Deep Clade test is not necessary.

Generations to Common Ancestor

The number of generations to a common ancestor for a 50% probability. This number is given under a MRCA column instead of a TMRCA column.

Contact Information

The name of the contact person is given, but the email address of that person is not given. Instead, the website will send your message to the contact person without divulging the email address of the person.

By Allen Leigh