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 DNA BASICS 101

 
What is DNA?   What is a Haplotype?  
What is a base pair?   What is linkage?  
What is a chromosome?   What is Haplogroup?  
What are autosomes?   What is a genetic polymorphism?  
What is a base sequence?      
What is a gene?   What is the testing process?  
What is a genotype?   When do I get my results?  
What is a genome? Other Interesting Links
    DNA related Maps  

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  

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.  top
 
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).  top
 
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
 
What is a Base Sequence?
The order of nucleotide bases in a DNA molecule; determines structure of proteins encoded by that DNA.  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.  top
 
A way of denoting the collective genotype of a number of closely linked loci on a chromosome.  top
 
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.   top
 
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.   top
 
Check out these websites:

 
 
Difference in DNA sequence among individuals, groups, or populations (e.g., genes for blue eyes vs. brown eyes).  top


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.

 

OTHER INTERESTING LINKS

Time to Most Recent Common Ancestry Calculator

World Haplogroups

Atlas of the Human Journey

The African DNA Project

Audio and Video Resources

Roots Television DNA Video

Interactive Haplo Chart