What Is Y-STR?
The Paternal Chromosome
The Y chromosome is passed exclusively by a father to his sons at conception. Unlike autosomal DNA which is reshuffled each generation, the Y chromosome remains virtually unchanged as it passes from father to son, grandfather to grandson, and beyond.
This means that all males in an unbroken paternal line carry the same Y-STR profile. If two males share the same Y-STR profile, they are related on the paternal line. If their profiles differ, they are not related on that line.
Paternal Line Inheritance
Great-grandfather ↓ passes Y
Grandfather ↓ passes Y
Father ↓ passes Y
Son ← same profile
Applications
When Y-STR Testing Is Used
Y-STR testing is a powerful tool for a range of paternal lineage questions.
Male Siblings
Establish or disprove a biological relationship between two alleged male siblings. If they share the same biological father, their Y-STR profiles will match.
Male Child & Uncle
A male child and his alleged paternal uncle should share the same Y-STR profile if they are biologically related through the paternal line.
Father Unavailable
When the alleged father is deceased or unavailable, a biological brother or grandfather of the alleged father can substitute — as they share the same Y-STR profile.
Genealogical Research
Y-STR profiles can be searched against global Y-STR databases to trace population ancestry and connect with distant paternal relatives across generations.
Test Details
Format & Turnaround
Available Formats
Y-STR testing is available for both personal and legal purposes. Both formats require participation from two or more questioned parties on the paternal line.
Turnaround Time
Results are delivered in 7–10 working days from receipt of samples. This longer turnaround reflects the additional complexity of Y-STR analysis compared to standard paternity testing.