In sexual assault investigations, what is the primary use of Y-chromosome STRs when female DNA is the major contributor?

In sexual assault investigations, what is the primary use of Y-chromosome STRs when female DNA is the major contributor?

• A. To determine the exact age of the DNA.
• B. To detect male DNA and help link the male contributor to the evidence.
• C. To identify the victim's hair color.
• D. To quantify total DNA.

Answer: (B)

Y-chromosome STRs target DNA present only in males, so in evidence where female DNA dominates, testing for these markers reveals whether male DNA is present and can link that male contributor to the evidence by comparing the Y-STR profile to a suspect or other samples from the case. This approach specifically helps establish male involvement even when female DNA is the major component. It does not tell you a person’s age, hair color, or how much total DNA is present. Also, because Y-STRs follow the paternal line, many unrelated males can share the same Y-STR profile, so they’re great for showing connection across samples but less definitive for unique identification.

Y-chromosome STRs target DNA present only in males, so in evidence where female DNA dominates, testing for these markers reveals whether male DNA is present and can link that male contributor to the evidence by comparing the Y-STR profile to a suspect or other samples from the case. This approach specifically helps establish male involvement even when female DNA is the major component. It does not tell you a person’s age, hair color, or how much total DNA is present. Also, because Y-STRs follow the paternal line, many unrelated males can share the same Y-STR profile, so they’re great for showing connection across samples but less definitive for unique identification.