What is Y-DNA?
Y-DNA refers to the DNA on the male sex chromosome – the Y chromosome. We each have 23 pairs of chromosomes: 22 pairs of autosomal chromosomes and two sex chromosomes – the X and Y chromosomes. Females inherit an X chromosomes from each parent (but no Y chromosome), while males inherit an X chromosome from their mother and a Y chromosome from their father. Very little recombination (mixing) occurs between the X and Y chromosomes in males, hence the Y-DNA essentially remains unchanged through the paternal line, providing an incredibly useful way to trace paternal ancestry.

What is the Y-DNA STR test?
The Y-DNA STR test is a useful technique used in ancestry, relationship and forensic applications. The test analyzes markers in the Y chromosome known as STRs or ‘short tandem repeats’. STR markers are short segments of DNA (2-13 nucleotides in length), which are repeated multiple times. STR analyses measure the exact number of repeat units. The number of repeats differs between individuals because STRs change frequently. The more closely related two individuals are along their direct paternal line, the more similar their Y-DNA STR profiles will be. Y-DNA STR tests can be used for forensic applications, investigating relationships, tracing distant male relatives who may have descended from the same paternal lineage and identifying links to famous people. It is a simple test that can provide you with rich information about your paternal lineage.

Methods and analysis of Y-DNA STR testing:
The Y-DNA STR Marker test uses a technique called polymerase chain reaction (PCR) to examine a defined set of STR markers in your Y-DNA. This technique determines the number of repeats at each marker tested – either 20, 44 or 101 markers, depending on the requested analysis.

When two individuals take the Y-DNA STR marker test, their STR numbers can be compared to see if there is a match. The confidence with which the Y-DNA STR test can predict a relationship between two individuals increases as more STR markers are tested. A calculation called “TMRCA” (time to most recent common ancestor) can be performed to estimate how many generations ago the two males likely shared a common paternal ancestor. Comparing more Y-DNA STR markers will provide a higher stringency comparison and a more precise TMRCA calculation.

Customers can select how many Y-DNA STR markers they would like to have analyzed:

• Standard Test: 20 STR markers.
• Advanced Test: 44 STR markers.
• Premium Test: 101 STR markers. This provides the highest resolution and most precise TMRCA calculation.

• Upgrade Options: A cost-efficient upgrade option is available, where customers can initially select just the Standard Test. If this test does not provide a high enough resolution, there is an option to upgrade to the Advanced Test or Premium Test.
• Combo Ancestry Test: Males are also able to analyze their maternal ancestry (in the Maternal Ancestry Test), hence males also have the option of analyzing both maternal and paternal ancestry concurrently in the DNA Ancestry Test – 2 Test Combo.