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DNA Test Procedure The
general procedure for taking a genealogical DNA test involves taking a painless
cheek-scraping at home and mailing the sample to a genetic genealogy laboratory
for testing. Some laboratories store DNA samples for ease of future testing. All
United States laboratories will destroy the DNA sample upon request by the
customer, guaranteeing that a sample is not available for further analysis. Types of Tests The
most popular ancestry tests are Y chromosome (Y-DNA)
testing and mitochondrial DNA (mtDNA)
testing which test direct-line paternal and maternal ancestry, respectively. DNA
tests for other purposes attempt, for example, to determine a person's
comprehensive genetic make-up and/or ethnic origins. Y Chromosome (Y-DNA) Testing A
man's patrilineal ancestry, or male-line ancestry, can be
traced using the DNA on his Y chromosome (Y-DNA) through Y-STR testing. This is useful because the Y chromosome
passes down almost unchanged from father to son, ie, the non-recombining and sex
determining regions of the Y chromosome do not change. A man's test results are
compared to another man's results to determine the time frame in which the two
individuals shared a most recent common ancestor
(MRCA). If their test results are a perfect or nearly perfect match, they
are related within genealogy's time frame (about 1000 years). Each
person can then look at the other's father-line information, typically the names
of each patrilineal ancestor and his spouse, together with the dates and places
of their marriage and of both spouses' births and deaths.
The two matched persons may find a common ancestor or MRCA, as well as
whatever information the other already has about their joint patrilineal
ancestry prior to the MRCA—which might be a big help to one of them. Or if
not, both keep trying to extend their patrilineal ancestry further back in time.
Each may choose to have their test results included in their surname's "Surname DNA project".
And each receives the other's contact information if the other chose to allow
this. They may correspond, and may work together in the future on joint
research. Women
who wish to determine their direct paternal DNA ancestry can ask their father,
brother, paternal uncle, paternal grandfather, or a cousin who shares a common
patrilineal ancestry (the same Y-DNA) to take a test for them. What Gets Tested A
chromosome contains sequences of repeating nucleotides known as “short tandem repeats”
(STRs). The number of repetitions varies from one person to another.
A particular number of repetitions is known as an “allele”
of the marker. Y-DNA testing involves looking at STR segments of DNA on the Y chromosome. The STR
segments which are examined are referred to as genetic “markers”
and occur in what is considered "junk" DNA. Understanding
Test results Y-DNA
tests generally examine 10-67 STR markers on the Y chromosome (over 100 markers
are available). STR test results
provide the personal haplotype for the individual being tested A
Y-DNA haplotype is the numbered results of a genealogical
Y-DNA test. Each allele
value has a distinctive frequency within a related population.
For tests utilizing a large number of markers the set
of allele
frequencies provide a signature for a surname lineage. The
test results may be compared to another person’s results to determine the time frame in which the two
people shared a most recent common ancestor
(MRCA). For example: If the two tests match perfectly on 37 markers, there is a
50% probability that the MRCA was fewer than 2 to 3 generations ago, 90%
probability that the MRCA was fewer than 5 generations ago, and 95% probability
that the MRCA was fewer than 7 generations ago. Our
Hale Y-DNA Test Results The
Y-DNA 37 marker haplotype for descendents of Joab Hale (abt 1760–1843) is
presented in the table below.
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