Not all single nucleotide polymorphisms cause a phenotypic change because sometimes the changes occur in the
A) coding region.
B) noncoding region.
C) promoter sequence.
D) telomeres.

Question

Quizplus · Accepted Answer

Single nucleotide polymorphisms (SNPs) are DNA sequence variations that occur when a single nucleotide in the genome differs between members of a species. SNPs occur in both the coding and noncoding regions of DNA, but only those that occur within coding regions can potentially affect protein structure and function, and therefore phenotypic traits. SNPs in noncoding regions, such as introns or intergenic regions, are less likely to cause a phenotypic change. Promoter sequences can also be affected by SNPs, but these too are noncoding regions. Telomeres are the protective ends of chromosomes and SNPs in these regions are less likely to cause a phenotypic change. Therefore, the best choice is B, noncoding region.

Not All Single Nucleotide Polymorphisms Cause a Phenotypic Change Because