Why are STR markers particularly useful in degraded DNA?

Why are STR markers particularly useful in degraded DNA?

• A. They are easier to interpret visually.
• B. They require no DNA at all.
• C. They have relatively short amplicon sizes, improving success with degraded DNA.
• D. They completely replace SNP analysis.

Answer: (C)

The main idea is that short STR markers are especially suited for degraded DNA because PCR targets are very short. Degraded samples break DNA into small fragments, so amplifying short regions around the STR core increases the chance that those targets remain intact and can be copied. This makes it more likely to obtain usable STR profiles from damaged material. Longer targets often can't be amplified when the DNA is broken, leading to partial or missing results. While STRs are highly informative for discrimination, they don’t imply no DNA is needed, nor do they completely replace SNP analysis; they simply offer a practical advantage in degraded samples due to their short amplicon sizes.

The main idea is that short STR markers are especially suited for degraded DNA because PCR targets are very short. Degraded samples break DNA into small fragments, so amplifying short regions around the STR core increases the chance that those targets remain intact and can be copied. This makes it more likely to obtain usable STR profiles from damaged material. Longer targets often can't be amplified when the DNA is broken, leading to partial or missing results. While STRs are highly informative for discrimination, they don’t imply no DNA is needed, nor do they completely replace SNP analysis; they simply offer a practical advantage in degraded samples due to their short amplicon sizes.