Y-STR MALE LINEAGE TESTING Male Lineage, or Y-STR, testing is a DNA test that specifically looks at the Y chromosome, which is present only in males. These tests are useful in determining relatedness through male lineage, although they are often more useful in disproving a relationship. If attempting to determine if male participants come from the same paternal lineage, the participants must share or suspect that they share a relative from whom they’ve descended along the same line of males. For instance, if attempting to determine if potential male cousins are true cousins, their fathers must be brothers who shared the same father. If the male lineage descends from the same male ancestor, the Y chromosome profile obtained through the test will be identical (mutations may occur) between the two potential male cousins, proving that they likely come from the same male lineage. If the participants do not have the same Y chromosome profile, they do not come from the same male lineage. While Y-STR testing is a useful tool to examine male lineage, this testing does not determine the specific relationship between two males within the same male lineage. Despite this, Y-STR testing can exclude males from a male lineage, and that can often be important information. For example, if an alleged father is not available for testing with a male child, you may use the alleged father’s brother (must be descended from the same father) or alleged father’s father. If the alleged uncle or paternal grandfather’s Y-STR profile does not match the child, the alleged father is most likely not the biological father. Y-STR testing is also frequently used on samples where you are looking for male DNA but there may be a lot of female DNA present (e.g. female underwear samples). In infidelity cases, where an individual may be looking to see if another male’s DNA is present, Y-STR is a good alternative to regular STR testing because it amplifies and examines ONLY male DNA, which can often be hard to detect in female underwear. If you are attempting to pursue a Y-STR DNA test, please contact GenQuest to discuss your situation and how to proceed. MITOCHONDRIAL FEMALE LINEAGE TESTING GenQuest now offers mitochondrial DNA testing! Mitochondrial (mtDNA) tests are used to determine relatedness through female lineage to help discover maternally-linked relationships. Unlike male lineage tests, participants in mtDNA tests can be male or female who suspect they share a relative through a maternal line. Mitochondrial DNA is passed on to children of both sexes through the mother. In a mtDNA comparison, analysts look at the mtDNA sequence of each participant side by side and if certain regions along the sequence are shared, this indicates that the participants share a common female ancestor through their maternal heritage, such as a mother or maternal grandmother. Like male lineage testing, mtDNA tests do not determine the specific relationship between participants, but only proves that they do or do not share a female ancestor along the maternal line. Difference between Lineage Testing and Ancestry Testing Ancestry testing (not available through GenQuest) traces your DNA back through several thousands of years to determine racial heritage and potential relatives in the company’s ancestry system. Paternal and Maternal comparisons are ways to confirm much more recent relationships in your male or female lineage. Often if ancestry testing identifies potential relatives, those findings can be confirmed with Y-STR or mtDNA testing. Visit our Interpreting Your Results page for details on how to interpret your Y-STR testing results.
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