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DNA BASICS 101
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What is DNA?
DNA, or deoxyribonucleic acid, is the hereditary material in
humans and almost all other organisms. Nearly every cell in a
person's body has the same DNA.
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DNA is a double helix or
spiral
"Sides of Ladder" are Sugars and Phosphates
"Rungs" are Base Pairs, usually A-T and C-G |
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What is a Base Pair?
Human DNA consists of about 3 billion bases, and more than 99
percent of those bases are the same in all people. The order, or
sequence, of these bases determines the information available
for building and maintaining an organism, similar to the way in
which letters of the alphabet appear in a certain order to form
words and sentences. DNA bases pair up with each other,
A with T and C with G,
to form units called base pairs. For example, two nitrogenous
bases (adenine and thymine or guanine and cytosine) held
together by weak bonds is called a base pair. Two strands of DNA
are held together in the shape of a double helix by the bonds
between base pairs.
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In the nucleus of each cell, the DNA molecule is packaged into
thread-like structures called chromosomes. Each chromosome is
made up of DNA tightly coiled many times around proteins called
histones that support its structure. Chromosomes are not visible
in the cell's nucleus--not even under a microscope--when the
cell is not dividing. However, the DNA that makes up chromosomes
becomes more tightly packed during cell division and is then
visible under a microscope. Most of what researchers know about
chromosomes was learned by observing chromosomes during cell
division. Chromosome 1 (the largest human chromosome) has the
most genes (2968), and the Y chromosome has the fewest (231).
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In humans, each cell normally contains 23 pairs of chromosomes,
for a total of 46. Twenty-two of these pairs, called autosomes,
look the same in both males and females. The 23rd pair, the sex
chromosomes, differ between males and females. Females have two
copies of the X chromosome, while males have one X and one Y
chromosome. top
A gene is the basic physical and functional unit of heredity.
Genes, which are made up of DNA, act as instructions to make
molecules called proteins. In humans, genes vary in size from a
few hundred DNA bases to more than 2 million bases. The Human
Genome Project has estimated that humans have between 30,000 and
40,000 genes. Every person has two copies of each gene, one
inherited from each parent. Most genes are the same in all
people, but a small number of genes (less than 1 percent of the
total) are slightly different between people. Alleles are forms
of the same gene with small differences in their sequence of DNA
bases. These small differences contribute to each person's
unique physical features. The average gene consists of 3000
bases, but sizes vary greatly, with the largest known human gene
being dystrophin at 2.4 million bases.
The genetic constitution of an organism, as distinguished from
its physical appearance (its phenotype).
All the genetic material in the chromosomes of a particular
organism; its size is generally given as its total number of
base pairs.
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A way of denoting the collective genotype of a number of closely
linked loci on a chromosome.
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The proximity of two or more markers (e.g., genes, RFLP markers)
on a chromosome; the closer the markers, the lower the
probability that they will be separated during DNA repair or
replication processes (binary fission in prokaryotes, mitosis or
meiosis in eukaryotes), and hence the greater the probability
that they will be inherited together.
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A Haplogroup is a group which consists of all of the direct
paternal or maternal descendants of a single individual (man or
woman) who had a specific mutation(s) and then passed this
specific mutation or genetic marker to their descendants.
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Check out these websites:
Difference in DNA sequence among individuals, groups, or
populations (e.g., genes for blue eyes vs. brown eyes).
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The Testing Process
How is the test
performed?
Your
genetic test kit consists of a cheek
scraper and a collection tube. In
about five minutes, you will be able
to read the instructions and perform
a painless cheek scraping. The
effect of using the scraper is about
the same as brushing your cheek with
a soft bristle toothbrush. A backup
scraper & tube is included to insure
that a good sample is obtained by
our lab. We intend that you use them
both!
The Test kit

The Family Tree
DNA test kit consists of two cheek
scrapers and two collection
tubes---designed for a single persons
use. Each tube contains a fluid designed
to arrest bacteria growth, so you can
scrape your cheek and return your kit in
any type of weather (hot or cold). The
freshness of your sample will remain
intact for months.
The prior collection standard of the
industry was the dry preservation
method, which worked without the fluid,
but in humid climates, was prone to
bacteria growth on the scraper tip.
FTDNA enjoys an international clientele;
therefore, we have chosen to use a
universal collection kit.
You will notice the cotton 'toothed' tip
at the end of the scraper. The sensation
of using our scraper is like brushing
your inside cheek with your toothbrush.
Remember, a good scrape produces lots of
DNA, which makes the extraction process
easier and decreases the chance that one
or more of your markers will fail to be
readable on the first test of your
sample.
Your kit also includes instructions for
collecting your DNA sample (available in
many languages) and the all important
Release Form. The Release Form is your
written consent that allows FTDNA to
share your name and email address with
someone who matches your genetic
fingerprint exactly.
We call these matches "Genetic Cousins
™", and they represent one of the most
exciting parts of the Family Tree DNA
system!
What is Family Tree
DNA?
Our service is
dedicated to helping
genealogists find
lost relatives when
the paper trail ends
and the brick wall
takes its place. We
use a painless cheek
scraping to obtain
DNA that can help
accurately determine
a relationship with
either a 99.9%
probability of YES
or a 100% certainly
that no near term
relationship
existed.
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Why would I want
to take a genetic test?
Our service was
created for the
serious amateurs and
the professional
genealogists who
wish to extend their
family trees by
confirming a link
where no
conventional source
records exist. In
some cases our tests
can also be used to
determine if a
person is part of a
larger group of
people: for example,
Jews will be able to
confirm they are of
Cohanim lineage. Our
tests are also
perfect for
individuals who want
to perform
Surname-based family
tree reconstruction
projects.
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What are the
costs of the tests
offered by Family Tree
DNA?
Our "mtDNA" test
used for both males
and females, and our
"Y-DNA" designed to
match males (often
with the same or
similar surnames)
are priced,
respectivelly at
$129 and $159. We
also offer a
"Y-DNA12+mtDNA"
which combines both
tests above (and is
for males who want
to test and database
both their mothers'
and fathers'
lineage). The
Y-DNA12+mtDNA is
$229. We also offer
the worlds' only "Cohanim"
test, which will
identify those
people who share
this set of markers
with the family of
the Biblical
character Aaron.
Our newest tests
Y-DNA37 ($289) and
mtDNAPlus ($189) are
designed to tighten
the time to the MRCA
by offering the
greatest number of
markers tested of
any genealogical
product on the
market.
Our Y-DNA and mtDNA
can also verify
Native American
ancestry for either
the male or female
side. They are
designed to tell you
from which
immigration to the
new world your male
or female family
progenitor arrived.
To successfully take
this test your lines
of descent must be
female to female to
female (or male to
male to male) all
the way back to the
person who was 100%
of Native Ancestry.
Please see our
Inheritance Chart
to insure you
qualify for this
test.
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Is it possible to
pay for a test to be
sent to another person
(third-party billing)?
Sure. In the
ordering process
there are 2 screens.
The first screen is
to enter the
information about
the person that will
do test. When you
advance to the
second screen, you
can enter the
billing information,
in case it is
different from the
individual that is
being tested.
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What do you do
with the results of the
tests?
Results will be
placed in our
secure, private and
confidential
database. Once a
person's test result
has been entered
into our genetic
library, a
connection can be
made whenever
another related
person chooses to
have their DNA
tested. For a better
understanding of the
privacy and
confidentiality
commitment of Family
Tree DNA, please see
our position on
Privacy &
Confidentiality
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How is your test
different from a
paternity test?
Family Tree DNA's
primary test
attempts to
determine if 2
people thought to be
unrelated actually
had a common
ancestor. Our
specific purpose is
to help recreate
lost family links.
Our test is for
genealogy NOT for
paternity, alimony
or other legal
purposes.
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What do these
Loci and Allele reports
look like; what do the
differences look like?
The report that we
will send you will
have various
information, along
with your personal
allele information.
We have listed
several examples of
these for you to see
here.
See Table #2
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How is the test
performed?
Your genetic test
kit consists of a
cheek scraper and a
collection tube. In
about five minutes,
you will be able to
read the
instructions and
perform a painless
cheek scraping. The
effect of using the
scraper is about the
same as brushing
your cheek with a
soft bristle
toothbrush. A backup
scraper & tube is
included to insure
that a good sample
is obtained by our
lab. We intend that
you use them both!
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Then what
happens?
After you have
placed your order, a
genetic test kit and
instructions will be
mailed to you. Upon
its' return your
genetic sample will
be processed, and
the results will be
entered into our
secure, private and
confidential
non-web-based
genetic library. A
comparison between
your specific
genetic markers and
those of others in
the database will
then be performed
and you will be
notified if another
person matches your
results perfectly.
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Will Family Tree
DNA have the right to
publish the results of
these studies?
No
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How do I place an
order for someone else?
Make sure you put in
the name of the
actual test taker in
the first screen of
the ordering
process.
Enter the address
the kit and the
results will be
mailed to. If this
is not the address
of the test taker
put “c/o" the person
receiving the kit,
on the first address
line. You can enter
the address on the
second line.
If you want the kit
sent to one address
and the results sent
to another address
enter the address
you want the kit
sent to. Once the
test taker has
received the kit and
returned it to our
office you may
change the address
to the one you want
the results sent to.
Enter the phone
number you wish to
use as the contact
number for this kit.
Enter the email
address(es) you want
to be notified of
the order and the
results. You may
enter more than one
email address.
Once you have filled
out the information
on this page click
“Continue” and fill
out the billing
information. Your
order will not be
processed until you
hit the “Confirm”
button.
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Will I have the
right to remove my
genetic profile from the
database at some later
time?
Yes. Just like an
email list, if you
decide that you want
your data deleted
from the database,
you may email us, we
will look up your ID
number, and ask that
it be deleted from
the Database.
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If the marker
analysis shows that I
carry a problematic
gene, will I be
informed?
No. We won't know if
you show positive
for a disease, as we
are only testing
your DNA to look at
12, 25 or 37
specific Loci on the
Y Chromosome.
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I am researching
a family with many
distinct branches. How
many people from each
branch should I use?
This is an important
and very practical
question that speaks
to the heart of
genealogical testing
and research. The
chance that a match
does not exist due
to infidelity or
unreported adoptions
occurs 2%-5% of the
time per generation.
For families trying
to do family
reconstruction, it
is prudent to test 2
different known male
cousins from each
different branch. In
cases of unexpected
results, FTDNA will
retest at no charge
to confirm that a
lab error is not an
issue. In case that
a retest is done and
the results are
confirmed, a $50
charge will be
applied.
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I am female and
another potential
relative is male. How
can we make a DNA
connection using Family
Tree DNA?
There are two ways
to answer this
genealogical
question. Ideally a
match would best be
done by testing a
known male member of
your biological
family, (brother,
father or first
cousin), against the
potential male
relative. This is
our Y chromosome
test which would
allow us to also
search for the
Cohanim gene.
The other method,
(not as straight
forward), utilizes
the mother who
passes her mtDNA to
both male and female
offspring and this
can be checked using
mtDNA or
mitochondrial DNA. A
match between the
mtDNA of a male
potential relative
and your mtDNA would
mean you have a
common female
ancestor. A male's
mtDNA comes only
from his mother and
is not passed on to
his offspring. This
is our Maternal
Match.
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16. How long will
it take for me to get my
results?
From the time you
return the two
specimens to us it
will take
approximately seven
weeks to test your
DNA sample, analyze
the specimens and
compare the results
to data in the
existing genetic
library.
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Suppose I have a
distant cousin in
another country and we
both send our specimens
separately, how will you
know that we want to
confirm our family
connections?
Unless you ordered
together or sent in
your samples
together we wouldn't
know that you wanted
to share results
with each other,
however this is not
a problem if you
sign the
Release Form,
included with every
test kit. When
signed we can then
automatically
release specific
contact information
to you and people
who have an exact
match to you. (We
invite you to test
us!) If you are
specifically testing
with another
individual just send
an email after you
place your order.
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How far back can
you determine a genetic
link?
All genetic tests
from Family Tree DNA
will provide you a
probability that you
and another person,
who have an exact
match, will have
your Most Recent
Common Ancestor (MRCA)
within a range of
time backwards. Our
12 marker test gives
you the following
range: 7 generations
(50%) likelihood &
29 generations (95%)
likelihood. Using
our 25 marker test
the 50% likelihood
drops to 3
generations and the
95% to 13
generations. The
37-marker test
tightens further to
2 generations (50%)
and the 95% to 7
generations. We have
also incorporated
all of our marker
mutations rates into
our new FTDNATiP
calculator.
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When should I use
a genetic testing
service?
We work in
conjunction with
existing
genealogical records
and our tests help
you fill in the gaps
where no records
exist.
To be clear, we can
determine descent
from your father's
father or your
mother's mother.
That means in the
case of an
individual's
great-grandparent's
generation, we can
determine a link to
two of your eight
great-grandparents.
You can, however,
easily determine
other family links
by obtaining DNA
samples from your
male and female
cousins.
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What is your
policy on
confidentiality and
privacy?
We understand the
extreme need for
privacy, even when
the goal is
genealogy rather
than courtroom or
medical
determinants. Much
has been written
about privacy and
confidentiality of
genetic testing over
the last 5-10 years,
and many states have
passed legislation
in this area. We
follow the most
stringent guidelines
for privacy: we
control the Surnames
Database Library,
while the University
of Arizona controls
and maintains the
genetic library on
our behalf.
Therefore, there is
a double safety net.
The first is upon us
in the form of State
legislation, and the
other upon the
University of
Arizona, which is
bound by both State
and Federal privacy
and confidentiality
legislation. To the
best of our
knowledge, no other
genetics testing
company has
voluntarily placed
itself under such
strict regulations.
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What steps does
Family Tree DNA take to
keep my results
confidential?
Your privacy is
assured because the
testing facility
will not have access
to your name. Only
your unique number
will accompany your
collection tube to
the testing lab. The
computer-generated
number is the only
information about
you that the testing
facility will see.
Once your test has
been completed, the
results will be
entered in a secure
non-web-based
database, and the
lab will inform us
of any matches
between two coded
numbers. The
information placed
in our Surnames
Database Library
will only display
your last name on
our web site. No
specific information
about you will be
available at the web
site.
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What does the lab
do with the actual DNA
sample once the test is
completed?
The DNA extracted
from your sample is
kept by the lab for
a period of 25 years
for your exclusive
use. It is important
to note that Family
Tree DNA adopts a
"double safety net"
in regard to your
sample: Arizona
Research Labs at the
campus of the
University of
Arizona keeps the
DNA associated to a
number and not a
name, while Family
Tree DNA offices
keep the database
with no access to
the actual sample.
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What is Family
Tree DNA's refund
policy?
If a kit is ordered,
paid for and unused,
we will give a full
refund if the order
was placed
mistakenly (person
does not fit into a
surname project).
If a kit is ordered,
paid for and unused
because the person
"changed his/her
mind", will will
give a refund, less
an amount that
covers for credit
card charges (in
case the kit was
paid by credit
card), shipping and
cost of the kit.
Those deductions are
$10 for orders under
$150, $15 for orders
from $151 to $250
and $25 for orders
from $251 to $500.
We won't give
refunds after kits
enter lab
processing. Delays
in processing a
scientific test can
happen, and
therefore we also
won't give refunds
in case of delays in
reporting results.
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OTHER INTERESTING LINKS
World
Haplogroups
Atlas
of the Human Journey
The
African DNA Project
Audio
and Video Resources
Roots
Television DNA Video
Interactive Haplo Chart
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