Question

The differences in the DNA of human individuals are due to

• A. Differences in allelic compositions
• B. Differences in number of STRs
• C. Differences in ethnicity
• D. Differences in blood groups

Answer 1

Answer: (A), (B)

Differences in number of STRs

99.9$\%$ of the DNA in every individual is the same. While allelic compositions of genes do differ in every individual, the most unique feature of an individual’s genome is the number of Short Tandem Repeats (STRs). These result in the 0.1$\%$ difference that exists among humans.