Parentage - Relationship Division
Y-Paternal Lineage Testing
The Y-STR paternal lineage test is used to determine whether or not two or more males are related through their fathers (through the paternal or male line). This test is often used to provide additional evidence in difficult paternity cases in which the alleged father is not available for testing or in cases where a single non-matching genetic system is observed between the alleged father and a male child. A single non-matching genetic variation in a paternity test is often the result of a mutation (a random change in the DNA which occurs in the formation of the sperm used for conception). This type of testing is only informative when the paternity of a male child is in question. The Y chromosome is passed from father to son relatively unchanged through many generations. The Y-paternal lineage test examines specific genetic markers on the Y chromosome to generate a Y-DNA profile for each male tested. Males who are related through their fathers will have the same or similar Y-DNA profile, where as males which are not related, are more likely to have different Y-DNA profiles. Although Y-paternal lineage DNA analysis cannot distinguish between males who belong to the same paternal line, it is useful for excluding males from an alleged biological relationship. For example, if the alleged father of a male child is not available for testing yet his brother (having the same biological father) is, then if Y-paternal lineage DNA testing is performed, the alleged uncle (alleged father's brother) and the male child will have the same Y-DNA profile. If they do not, then the alleged uncle is excluded (not considered a biological uncle) and the alleged father is most likely not the true biological father of the male child.