In a comparison of two DNA sequences found in the same location on homologous chromosomes, one of the homologs carries the sequence 5′-AACTACGA-3′, and the other homolog carries the sequence
5′-AACTTCGA-3′. Within a population, you discover that each of these sequences is common. Which of the following statements correctly describes theses sequences?
A) They contain a SNP that may be useful for genetic mapping.
B) They can identify a protein-coding region of a gene.
C) They may cause disease.
D) They may carry out RNA interference.

Question

Quizplus · Accepted Answer

The two sequences differ by a single nucleotide polymorphism (SNP), specifically a substitution of T for C. This SNP can be used as a genetic marker for mapping loci of interest in the population. The other choices are not supported by the information given. There is no evidence that these sequences identify protein-coding regions or cause disease, nor is there any information suggesting that they are involved in RNA interference.

In a Comparison of Two DNA Sequences Found in the Same