Y- Chromosome Testing

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.

The Y-Chromosome has definable segments of DNA with known genetic characteristics. These segments are known as Markers. These markers occur at an identifiable physical location on a chromosome known as a Locus. Each marker is designated by a number (known as DYS#), according to international conventions. You will often find the terms Marker and Locus used interchangeably, but technically the Marker is what is tested and the Locus is where the marker is located on the chromosome.

Although there are several types of markers used in DNA studies, the Y-Chromosome test uses only one type. The marker used is called a Short Tandem Repeat (STR). STRs are short sequences of DNA, (usually 2, 3, 4, or 5 base pairs long), that are repeated numerous times in a head-tail manner. The 16 base pair sequence of "gatagatagatagata" would represent 4 repeats of the sequence "gata". These repeats are referred to as Allele. The variation of the number of repeats of each marker enables discrimination between individuals.

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 or MRCA. If their test results are a perfect, or nearly perfect match, they are related within genealogy's time frame.
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. This information table will be referred to again within the mtDNA testing section below as the (matrilineal) "information table". 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.
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.
A chromosome contains sequences of repeating nucleotides known as short tandem repeats (STRs). The number of repetitions varies from one person to another and a particular number of repetitions is known as an allele of the marker. Y-chromosome STRs are assigned names by the HUGO nomenclature committee. The example below shows the allele of Rumpelstiltskin's DYS393 marker is 12, also called the marker's "value". The value 12 means the DYS393 sequence of nucleotides is repeated 12 times—with a DNA sequence of (AGAT)₁₂.

Prenatal Testing

If you have had more than one partner, it is natural for you to want to know who the father of your baby is. Different reasons to establish paternity include the need to collect support financially or emotionally, or simply for the peace of mind.

Parental testing is the use of genetic fingerprinting to determine whether two individuals have a biological parent-child relationship. A paternity test establishes genetic proof as to whether a man is the biological father of an individual. Though genetic testing is the most reliable standard, older methods also exist, including ABO blood group typing, analysis of various other proteins and enzymes, or using human leukocyte antigen antigens. The current techniques for paternal testing are using polymerase chain reaction (PCR) and restriction fragment length polymorphism.

A DNA paternity test can be performed accurately before a child is born through amniocentesis, chorionic villus sampling and NON-Invasive prenatal paternity testing at between 8 - 13 weeks into the pregnancy. There are a few companies in the USA and Canada that claim they are doing this type of testing.

DNA testing can be done as early as the end of the first trimester of pregnancy, starting in the 10th week by the CVS procedure. It is a rule of most DNA laboratories to keep your results completely confidential. Speak with each laboratory individually on their policies concerning confidentiality. Prenatal DNA testing done in conjunction with other prenatal testing involves some risk associated with how the testing is conducted, whether amniocentesis or CVS. These tests are often discouraged for the sole reason of seeking paternity because of the increased miscarriage risks.

There are a number of DNA and paternity testing facilities around the country. You want to make sure you use an facility accredited by the AABB. You may be interested in comparing different testing facilities.

DNA Diagnostics Center is the official paternity testing organization of the American Pregnancy Association. They are actively involved with the AABB and receive APA's endorsement for their quality services.

Paternity testing from an accredited laboratory typically costs between $400.00 and $2,000.00, depending on the area in which you live in and the type of paternity testing you choose. The American Pregnancy Association recommends paternity testing from a testing facility that has been accredited by the AABB such as DNA Diagnostics Center. Results are usually available to the patient in 2 business days. 

Why is establishing Paternity important?

Committing paternity fraud or providing false information about the identity of a child on a "Statement of Live Birth", the form used to register a birth in Ontario or on a similar form in other provinces or territories with registrars of vital statistics, is a serious matter.

In some provinces the statute may say that providing false information has a maximum penalty of a fine of $100,000 plus 6 months in jail.

Establishing paternity is important to ensure a child’s wellbeing and to fully protect his or her rights. Definitively knowing one’s biological parentage is important for several reasons:

• It allows access to legal and social benefits, including social security, veteran’s, and inheritance benefits.
• It provides an accurate medical history for the child, giving the healthcare provider additional insight during diagnosis and in managing the child’s health.
• It strengthens the bond between father and child.

If there is a question on who the father is, paternity testing should be done as soon as possible. Most states have laws that require an unmarried couple to fill out an Acknowledgment of Paternity (AOP) form at the hospital to legally establish who the father. If the couple is unmarried and the mother has not been married in the last 300 days, then no father will be listed on the birth certificate until this legally binding form is filled out. The AOP is sent to the states Bureau of Vital statistics, is recorded, and the father listed becomes the legal father.

After the AOP is signed, couples have a limited amount of time, depending on the state, to request a DNA paternity test to be done and amend the AOP; if this is not done, the father previously listed on the AOP could be held legally responsible for the child even if he is not the biological father.

Prior to signing the AOP, if the alleged father is not certain he is the biological father, he can privately get a paternity test. Test results from accredited labs like DNA Diagnostics Center are recognized as legal documents in all 50 states, can be completed in just 2 days, and can be used to legally establish paternity.

If the mother is married to someone other than the father of the baby or has not been divorced for over 300 days, her husband is presumed to be the father of the baby. The biological father can only be named the legal father if he fills out an AOP and the husband also signs a denial of paternity. If the husband does not sign the denial of paternity, then either biological parent would need to take action in court to establish true paternity.