See also: donsnotes.com/science/biology/dna_genealogy.html

What is DNA testing? Most people have heard of genes which are contained in 23 pairs of chromosomes made of "DeoxyriboNucleic Acid" (DNA) which are contained in every cell in our bodies. These are inherited from our parents and can be used to make some comparison of who our ancestors are.

For Genetic Genealogy, which is the application of DNA testing to genealogy research, three types of DNA can provide information useful in conjunction with genealogy research. These types are the Y chromosome (Y-DNA), Mitochondrial (mtDNA) and autosomal (auDNA).

y-DNA - The Y-chromosome only exists in males, so is used for tracing male lines.

Mitochondrial DNA (mtDNA), is passed only in the egg outside the cell nucleus, so comes from your Mother and is useful for tracing female lines.

There are several companies where you can get your y-DNA tested.
The most popular is Family Tree DNA (FamilyTreeDNA.com)
Others are:
23andMe - Genetic Testing for Ancestry; DNA Test
DNA Tests for Ethnicity & Genealogical DNA testing at AncestryDNA
OxfordAncestors.com

Pioneer - Exploratory Gene
Sikes DNA analysis
McBride DNA analysis
Summary of DNA and genealogy

Interpreting Genetic Distance Within Surname Projects for 25 marker test at www.familytreedna.com/genetic-distance-markers.aspx

  • Distance: 0 - Related

    Your perfect 25/25 match means you share a common male ancestor with a person who shares your surname (or variant). These two facts demonstrate your relatedness

  • Distance: 1 - Related

    You share the same surname (or a variant) with another male and you mismatch by only one 'point' on only one marker. For most closely related and same surnamed individuals, the mismatch markers are usually either DYS 439 or DYS 385 A, 385 B,389-1 and 389-2 from our first panel of 12 markers, and on the following from the second panel: DYS #'s 458 459 a 459b 449, 464 a-d, which have shown themselves to move most rapidly. The probability of a close relationship is very high.

  • Distance: 2 - Probably Related

    You share the same surname (or a variant) with another male and you mismatch by two 'points' among the 25 markers we tested. For most closely related and same surnamed individuals, the mismatch markers are usually either DYS 439 or DYS 385 A, 385 B,389-1 and 389-2 from our first panel of 12 markers, and on the following from the second panel: DYS #'s 458 459 a 459b 449, 464 a-d, which have shown themselves to move most rapidly. The probability of a close relationship is good, however your results show mutations, and therefore more time between you and the other same surnamed person.

  • Distance: 3 - Probably Not Related

    You share the same surname (or a variant) but are off by 3 'points' or 3 locations on the 25 markers tested. If enough time has passed it is possible that you and another distantly related family members' line each have had a mutation, or perhaps 2. The only way to prove that is to test additional family lines and find where the mutation took place. Only by further testing can you find the person in between each of you... this in 'betweener' becomes essential for you to find, and in their absence the possibility of a match exists, but further evidence should be pursued.

  • Distance: 4 - Not Related

    21/25 is too far off to be considered related. Unlikely but vaguely possible that the rule for ONLY "Probably Not Related" applies. It is important to determine what set of results (or haplotype) most typifies 'most' members of the group you are close to matching. You may be 21/25 with an individual, but 23/25 with the center (most common) of the group, and your potential relatedness to him is through the center of the group.

  • Distance: 5 - Not Related

    20/25 You are not related and the odds greatly favor that you have not shared a common male ancestor with this person in excess of 2,000 years.

  • Distance: 6 - Not Related

    Y19/25 You are not related and the odds greatly favor that you have not shared a common male ancestor with this person in excess of 5,000 years.

  • Distance: > 6 - Not Related

    You are totally unrelated to this person.

See Also:
Computing Genetic Distances

Return to Califorina Settlers.

last updated 20 June 2007