By Dexter Montgomery
DNA testing for Genealogy, called Genetic Genealogy, is
a powerful new tool, which is used in conjunction with family history
research. This new tool provides new information, often information that
cannot be uncovered from other sources.
DNA testing can:
Determine if two people are related
Determine if two people descended from the same
Confirm your family tree
Find out if others with your surname are related
Prove your research
Prove or disprove a research theory
Find others to whom you are related
Get clues about your ethnic origin
Confirm a suspected ancestral adoption
Provide clues to find the Ancestral village
Determine the points of origin for a surname
DNA testing for Genealogy is Not a substitute
for family history research. It is a tool to be used in conjunction with
family history research. There are two basic types of DNA tests available
for Genealogy: Y DNA Tests and mtDNA Tests.
The Y DNA test are only available for males, since the
test involves testing a small portion of the Y chromosome, which is passed
from father to son. Males have both an X and a Y chromosome. They receive
the X chromosome from their mother, and the Y chromosome from their
father. Females have two X chromosomes, one each from their father and
Both males and females inherit mtDNA from their
mothers. Testing mtDNA provides information about the direct female line
of the person, which would be their mother, their mother’s mother, and so
forth. MtDNA testing provides information about the original ethnic origin
of your direct female ancestral line. The result of the mtDNA test would
tell you which of the original daughters of Eve was your ancestor. MtDNA
testing can also be applied to your genealogy research. An example of
utilizing mtDNA testing for genealogy would be where an ancestor had two
wives, and multiple daughters, and you want to determine which daughters
had which mother. In this case, you would need to find direct descent
female descendents of the daughters, and test them. Lets assume that
Daughter 1 is documented with Mother A, and Daughter 4 is documented with
Mother B. You are uncertain of the mother for Daughters 2 and 3. You would
find female descendents of the daughters, in the direct female line, and
test 1 descendent of each of the 4 daughters. The descendents of Daughter
1 and Daughter 4 should have different results, and depending on which of
these results the descendents of Daughter 2 and 3 match, tells you whom
the mother was of Daughters 2 and 3.
Because the Y chromosome typically follows surnames,
there is a much wider range of applications for Y DNA testing, and a much
broader spectrum of problems which can be solved, and information that can
be acquired. Therefore, the balance of this article will focus on Y DNA
Scientists have discovered a small portion of the Y
chromosome is passed from father to son. It is located in the region
called Junk DNA, and is not involved in determining our personal
characteristics. Locations in this section of the Y chromosome are called
Markers, and these Markers change at a rate of about once every 500
generations per Marker. When these locations, or Markers, are tested, the
result is a numerical score for each Marker, reflecting a count of the
proteins found. Below are some example results:
14 22 14 10 13 14 11 14 11 9 11 25
15 23 15 10 15 16 13 13 11 14 12 30 16 8 9 11 11 26 15 20 29 12 12 15 17
13 23 14 10 13 14 11 14 12 12 11 28 14 8 9 8 11 23 15 20 28 13 15 16 17
The first line of results illustrates the results of a
12 Marker Y DNA test. The next two lines are an example of a 25 Marker Y
DNA test results.
The value of DNA testing comes in to play when
comparing results of two or more males. By comparing the three (3) results
shown above, we can determine that these people are not related in a
genealogical time frame. None of the results match each other.
In the example below, we have the Y DNA test results
for two people, who wanted to determine if they were related, and
therefore had a common ancestor.
13 25 15 11 11 11 12 12 10 13 11 31 17 9 10 11 11 23 14
20 33 14 16 16 17
13 25 15 11 11 11 12 12 10 13 11 31 17 9 10 11 11 23 14 20 33 14 16 16 17
As you can see, the results match. This match is called
a 25/25 match, since all 25 markers match between the two results.
In the example below, which is a 24/25 match, the two
people are related, but most likely at a more distant time. In the example
below, for the 24th marker, one person has a 16, and one person
has a 15. A mutation, or change, has occurred for this marker.
13 25 15 11 11 11 12 12 10 13 11 31 17 9 10 11 11 23 14
20 33 14 16 16 17
13 25 15 11 11 11 12 12 10 13 11 31 17 9 10 11 11 23 14 20 33 14 16 15 17
Since the Y chromosome is passed from father to son,
the male direct line of descent must be followed when considering test
candidates. Since females cannot participate, they often ask a direct
descent male relative to participate.
The first step to utilizing DNA testing for Genealogy
is to determine your objectives. What do you want to achieve? What is the
research problem which you want to solve or for which you want to discover
clues? Do you want to confirm your research, or determine the points of
origin for your surname? Objectives are dependent upon your specific
family history situation, and what you want to achieve.
The second step is to determine whom to test. Whom you
test, and which test you select, depends on the objectives of your
Below are some example objectives, a description of the
situation, and whom you would select to test.
Objective: Confirm research
Situation: You have only been able to find limited documentation that
connects 3 sons to Epha.
Testing: Y DNA testing can be used to confirm your research. Test 1
descendent of each of the 3 sons. Their Y DNA test results should match or
be a close match. A match is 12/12 or 25/25. A close match would be 11/12,
23/25 or 24/25. It is important to note that the testing results alone
will not say that the Father is Epha. The test results combined with your
family history research confirms your research. The test results without
the family history research simply says that the people are related, and
had a common ancestor, and an approximate time frame of the common
ancestor. The test results alone do not identify the common ancestor.
Identifying the common ancestor is the role of the family history
Objective: Confirm suspected Adoption
Situation: From your family history research, it "appears" that Epha took
in a neighbor’s son and the son took on Epha’s surname. It is possible
that the son was born in a different village to Epha’s wife, and you just
haven’t found the entry.
Testing: Test one male descendent of one of Epha’s documented sons, and a
male descendent of the suspected adopted son. If they match, or are a
close match, they both had a common ancestor. If they do not match, then
your theory is confirmed. It is important to note that the Y DNA test does
not identify the common ancestor. If Epha took in a son of one of his male
relatives, such as his brother, then the results of the descendents would
match, even though they are not both Epha’s sons.
Objective: Determine if the two families with the same surname are related
Situation: You have found another family with the same surname, whose
ancestors also came from the same village. You want to find out if they
Testing: Test one direct descent male from each line. If they match, or
are a close match, they are related.
Y DNA testing has many applications, depending on the
situation, and is a powerful tool which is used in conjunction with family
history research. Y DNA testing alone will not:
Identify the specific common ancestor
Identify where the ancestor lived
Provide a name for the ancestor
Y DNA testing is frequently used in Surname Projects.
Surname Projects involve testing one or two males from each identified
Line of a surname, to determine which Lines are related, and therefore
have a common ancestor. Surname Projects will also identify the number of
origins for a Surname. In addition, Surname Projects often provide clues
for further family history research and locations for research, and save
The largest commercial testing company providing
Genetic Genealogy testing services is Family Tree DNA, located in Houston,
Texas. Family Tree DNA offers a wide variety of DNA tests for genealogy,
at very affordable prices. All DNA tests from Family Tree DNA include
lifetime matching in their large data base of results.
Family Tree DNA also has a unique set of tools
available to assist in managing a Surname Project. These tools make is
easy to manage a project, and saves the Project Manager a significant
amount of time. These tools also enable some one with no prior experience
to start and effectively manage a Surname Project.