The main difference between the AncestrybyDNA test, which is an autosomal test,
and the basic genetic genealogy tests such as the Y-chromosome used for the Surname Projects
or the mitochondrial (mtDNA) tests used for the direct female descent, is that
it surveys across all 23 chromosome pairs, not just one of them as is the case
of the Y-DNA test.
The ANCESTRYbyDNA test will measures a person's Personal Anthropology and
their corresponding ancestral ethnic proportions. The result of the test is a
report showing your percentages of each ethnic ancestry or major human
population group. For example, your result could be 18% Native American, 70%
European, and 12% African.
The AncestrybyDNA test looks at SNP's that are diagnostic
of a person's continent of origin. SNP's are deep ancestral locations along the
human genome. Therefore, the results of this test tells you about your ancestors
far before the advent of genealogical records or surnames. Therefore, if you
receive a result that shows 85% European and 15% Asian, most likely you will not
find genealogical records to support this mixture, since the events occurred
before written records.
Most people of European ancestry are a mixture of two or
more of the major
population groups: European, Native American, East Asian and
sub-Saharan African. The AncestrybyDNA test results report your mix.
If you get
a result such as 85% European and 15% Asian, this does not mean that you had an
ancestor that was 100% Chinese. What it means is that you had several ancestors
who had some component or percentage of Asian ancestry.
The AncestrybyDNA test is a great opportunity to explore
your heritage beyond the time of written records. To order the test, use the
following URL:
http://www.AncestrybyDNA.com
When you obtain this anthropology test from DNAPrint, you
will receive a CD-ROM 
with your raw genetic data, a bar graph showing the
percentages of each group and a specialized representation of your data called a
triangular plot, along with a users manual. Ancestry cannot yet be determined by
any genetics test in a black and white litmus test fashion. Instead, the results
are reported as statistical estimates, and are qualified with confidence
intervals. DNAPrint estimates these tests are accurate to 4 - 8% and sensitive
enough to detect, for many a single African or European 2nd great grandparent,
or a single Native American or East Asian great grandparent.
The AncestrybyDNA test should primarily be used as an
attempt to confirm recent admixture events, where your family tree is primarily
European (for example), but one or more recent ancestors are of another
ancestry, such as Native American.
How the AncestrybyDNA.Com Test Works
To determine your Ancestry, DNAPrint extracts DNA from
your buccal sample (mouth swab). The AncestrybyDNA test then determines the
sequence of your DNA at a large number of different positions (across all of
your chromosomes). The buccal sample that you return to the lab for testing
contains thousands of cells, and each of your cells contains your DNA. Though we
(humans) are all 99.9% identical at the level of our DNA sequence, there are
certain regions of each chromosome that are different from person to person.
These regions are called genetic markers or Single Nucleotide Polymorphisms (SNPs),
and it so happens that some small fraction of these SNPs are also different
among the world’s continental population groups. These types of markers are
best termed Ancestry Information Markers (AIMs) and they contain less than 5% of
our genetic material, which is related to the very recent common origin of our
species.
The positions in your DNA sequenced in the AncestrybyDNA
test are those discovered by the genetic scientists have discovered that are
different in this way, and they are spread across all of your chromosomes.
Therefore, this test is referred to as a ‘genomics’ test, because it is a
survey of all of your genetic material, which is known as your ‘genome’.
In
other words, this test sequences markers from chromosome 1, 2, 3 thru 22. The
Y-DNA tests discussed in other sections of DNA - 101 are concerned with a
single chromosome (#23).
Your DNA was derived from your mother and father, and
theirs was derived from their mothers and fathers, and theirs from their parents
and so on. You have 23 pairs of chromosomes. Your maternal copy of chromosome #1
could have been passed through your mother from your maternal grandmother, or
your maternal grandfather, but which one you received was randomly determined at
conception (you could not have received both). Most of the time this inherited
chromosome #1 copy that you receive from your mother is actually a chimeric
chromosome that includes parts from your grandfather and your grandmother, a
process known as recombination.
Recombination is the process by which these chimeric
chromosomes are created and occurs at least once on each chromosome every time a
new sperm or egg cell is made. As such, although blending does not occur at the
level of the gene (the unit of trait expression) our chromosomes are mixed
together and so our genomes contain segments of DNA from ALL of our ancestors
(think about the significance of that for a minute). In contrast, the
mitochondrial DNA or Y-chromosome tests provide data on only a single lineage of
ancestors. For example, a baby born today would have 1,024 potential ancestors
10 generations ago or about the year 1700. By measuring your ancestral
proportions using a genomics method, the AncestrybyDNA test is actually
measuring ancestors. By measuring your ancestral proportions using a genomics
method, the test is actually measuring the average population affiliations of
all of these 1,024 ancestors.
Since random processes (recombinations and independent
assortment) at inception determines the mixings and pairings you harbor, two
offspring from a set of parents may have different sets of chromosome pairs, and
therefore different ancestral proportions even though they were the product of
the same male-female union. For example, a European male who married an Hispanic
woman had three children of mixed descent. Each of the children exhibits their
own unique proportionality, which you can see by visiting:
http://www.ancestrybydna.com/casestudy.pdf
If these two had an infinite number of children. The average would correspond
to that proportionality exactly between the mother and father, but each child
would deviate from this average by a unique and random amount.
Director:
Robert B. Noles
American descent (Native American heritage is usually hard to
prove by traditional documentation, but is usually true)? Are you or one of your
ancestors adopted and curious about your heritage? Are you predominantly
of African descent and curious about other ancestry you may have? Do you
want to expand and confirm your family’s heritage beyond the traditional time
frame of a few hundred years?
Native
American
- Those people who migrated from Asia
to inhabit North, South and Central America approximately 12,000 years ago.
