The U.S. Department of Justice has established a database that catalogs PCR amplification products from short tandem repeats of the Y chromosome (Y-STRs) in humans. The database contains polymorphisms of five U.S. ethnic groups (African-Americans, European Americans, Hispanics, Native Americans, and Asian-Americans) as well as the worldwide population.

Y-STRs from the nonrecombining region of the Y chromosome (NRY) have special relevance for forensic purposes. Why?

Key Concepts

Y-Chromosome and Nonrecombining Region (NRY)

The Y chromosome is one of the two sex chromosomes in humans, determining male biological characteristics. The nonrecombining region of the Y chromosome (NRY) is crucial because it does not undergo recombination during meiosis, allowing it to be passed down unchanged from father to son. This stability makes Y-STRs particularly useful in tracing paternal lineage and studying male ancestry.

Short Tandem Repeats (STRs)

Short tandem repeats (STRs) are repeating sequences of 2-6 base pairs of DNA found in various locations throughout the genome. They are highly polymorphic, meaning they vary greatly among individuals, making them valuable for genetic profiling in forensic science. The analysis of Y-STRs can help identify male individuals in mixed DNA samples, which is essential in criminal investigations.

Forensic Genetics

Forensic genetics involves the application of genetic analysis to legal investigations, particularly in identifying individuals based on biological evidence. The use of Y-STRs in forensic contexts is significant because they can provide insights into male lineage, especially in cases of sexual assault or paternity testing. This specificity enhances the accuracy of identifying suspects or victims in forensic cases.