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There are
currently two main types of DNA tests available in support of Genealogical Research: Y-DNA tests
and mtDNA tests.
There is also a test that provides information about your ancestral mix,
called the DNAPrint test.
The Y-DNA test is
only available for males, since the test involves testing a small portion of the
Y-chromosome,
which is passed down from father to son, generation after generation . Males have both an X and a Y-chromosome.
Males 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 mother.
Testing
the Y-DNA provides information about the direct male
line, which would be the father, his father, his father, and so forth, back in
time. Scientists
have discovered that a the Y-chromosome
is passed from father to son, virtually unchanged. Therefore, if a father and
son are tested, their results would match.
If
two cousins who have the same grandfather, great grandfather, etc., are tested, their results would
also match
or be a very close match.
By comparing the result from a Y-DNA
test of two males, you can determine if they are related and approximately when
their
common ancestor occurred.
The locations
tested on the Y-chromosome for the Y-DNA
test are called markers. There are 3 versions of the Y-DNA
test available:
 Y-DNA12
test
is for
12
Markers
Y-DNA25
test
is for
25 Markers
Y-DNA37
test
is for
37 Markers
Y-DNA67
test
is for
67 Markers
The 25-marker test includes the markers that are tested
in the 12-marker test. The 37-marker
test includes the markers tested in the 25-marker test.
If a person starts with the 12-marker test, they
can later upgrade to either the 25-marker test, 37-marker or the 67-marker
tests at a later date. The 25-marker
test can also be upgraded to 37-markers.
Selecting the
number of markers to test
may be a budget consideration. More
markers will provide a smaller estimated time
frame for the common ancestor (and a greater assurance of
proof). The 12-marker
test can establish that two males do not have a common ancestor in a
genealogical time frame.
For all other
applications, the 25-marker, 37-marker or 67-marker
test is recommended. The additional information from the 37-marker
test far exceeds the incremental cost. When the budget is available, select the
37-marker
test.
 Because the Y-chromosome typically follows a
surname,
there is a much wider range of application in genetic genealogy for
Y-DNA
testing. In
addition, the Y-DNA
test can resolve a broad spectrum of problems, and provides information about
the direct male line.
Y-DNA
testing is frequently used in what are called Surname Projects. Surname Projects involve
testing two or more males from each identified line of a surname, to determine which lines
are related, and therefore which ones have a common ancestor.
Surname Projects can 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, as well as save people research time with the clues
provided by the Y-DNA test results.
In
1998, a Y-DNA test conducted before such testing was widely available and
inexpensive, indicated that Thomas Jefferson or one of his direct line relatives
(such as a brother or uncle) fathered at least one child born to a slave at
Jefferson's Monticello estate.
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
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.
There are situations 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.
For example:
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.
The
mtDNA test is available in 2 versions. These tests are called:
mtDNA
mtDNA
Plus
The test called mtDNA provides a result for the region of mtDNA
called HVR1. The test called mtDNA Plus tests two regions of mtDNA, HVR1
and HVR2.
Anyone with an understanding of family history research can utilize
DNA testing. It isn't necessary to have a scientific background. The
few scientific terms you will encounter are explained. It
is easy to get started. Typically,
you would want to start with a test of your direct male line and your direct
female Line. If you are female, you would need your father or
brother or other close male relative to participate for the Y DNA test to
represent your direct male line.
If you are interested in DNA testing for a
surname line other than Knowles (all spellings), you
can check at Family Tree DNA to see if there is a Surname Project established
for your direct male
line
has already been established. You can perform a search by
using
the link
listed
below:
http://www.familytreeDNA.com/surname.asp
To
order a Y-DNA
test
and/or an
mtDNA
test, use the
following link:
http://www.familytreeDNA.com/products.html
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Director:
Robert B. Noles
