Imagine that you compare two DNA sequences found in the same location on homologous chromosomes. On one of the homologs, the sequence is AACTACGA. On the other homolog, the sequence is AACTTCGA. Within a population, you discover that each of these sequences is common. These sequences
A) identify a protein- coding region of a gene.
B) cause disease.
C) protect against disease.
D) contain a SNP that may be useful for genetic mapping.
E) none of the above.

Question

Quizplus · Accepted Answer

The difference in the two DNA sequences (T vs. C) represents a single nucleotide polymorphism (SNP) that can be used for genetic mapping. SNP markers are useful for identifying disease genes or tracing the inheritance of a particular trait in a family or population. The fact that both sequences are common in the population suggests that this SNP is not associated with a phenotype (i.e. it is not causally linked to a disease or trait).

Imagine That You Compare Two DNA Sequences Found in the Same