The U.S. Department of Justice has established a databas...

Question

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.

What would be the value of knowing the ethnic population differences for Y-STR polymorphisms?

Accepted Answer

Hello everyone. Let's look at our next problem. It says why STRS from the N. R. Y. Are useful for forensic purposes because they can be used to. So just to introduce our problem, let's briefly recall what are Y STRS and what is the N. R. Y. The Y STRS are short term repeats on the Y chromosomes. So areas on the Y chromosome where you have short term repeating DNA sequences and these are variable in lineages. So different male lines can have different numbers of these repeats. So they can be used to distinguish among related versus unrelated men. The N. R. Y. Is the non recombining region of the Y chromosome. It's that region that is not at all homologous with the X. Chromosome. There can be no recombination of genetic elements or genes from the maternal and paternal lines. So it's pretty highly conserved from father to son over the generations. So these short term repeats. They vary among their past reliably from father to son but very among unrelated males. So their usefulness and forensic purposes. So if you have a D. N. A. Sample and you're trying to identify you know a criminal who left the sample. They are useful to choice. D identify male suspects and determine patria, patra, lineal lineage. So you can look at these why STRS and determine if a suspect is related in the male line to some known sample you have. So let's look at our other answer choices to understand why they're not correct um Choice a determine an individual's height choice be determined an individual's blood group. Well that will not be genetically determined by uh sequences in the Y. STR. Region. Those genes are elsewhere in the genome. So that is not its usefulness in forensics. Choice C determine an individual's gender. Well, if you're analyzing the Y chromosome, you're already looking at the male most likely um otherwise in combination with the other sex chromosomes. So that's not the usefulness of these particular regions compared to choice D. Or answer identifying male suspects and determining patra lineal lineage in a more specific way. So again, our answer choice choice D. Y. S. T. R. N. R. I N. R. Y. Are useful for forensic purposes because they can be used to identify male suspects and determine patra lineal lineage. See you in the next video.

Key Concepts

Y-STR Polymorphisms

Ethnic Population Genetics

Forensic Applications

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