Question

genetic mutations produce variation quick check
what is one way that a frameshift mutation could occur? (1 point)
two nucleotides are substituted
two nucleotides are deleted
three nucleotides are inserted
three nucleotides are deleted

Explanation:

A frameshift mutation occurs when the addition or deletion of nucleotides changes the reading frame of the genetic code (since the code is read in groups of three nucleotides, codons). Substitution of nucleotides is a point mutation and does not shift the frame. Insertion or deletion of a number of nucleotides that is not a multiple of three will shift the reading frame. Deleting two nucleotides (not a multiple of three) will cause a frameshift, while inserting or deleting three nucleotides (a multiple of three) would add or remove a whole codon, not causing a frameshift (it would be an in - frame insertion/deletion). Substitution (two nucleotides substituted) is a point mutation and doesn't cause a frameshift.

Answer:

B. two nucleotides are deleted