Question

When considering the role of mutations on allele frequency changes through time, the occurrence of back mutations (that fix the mutation) are often ignored. Which of the following statements best describes why this is the case?

1) This is not problematic because back mutations cannot occur.
2) This is not problematic because the back mutation rate is so low.
3) This is problematic, but needs to be done because of simplicity.
4) This is problematic, but geneticists are not sure why.

Answer 1

Back mutations are typically ignored in allele frequency studies because their rates are significantly low, resulting in a negligible effect on overall genetic variation and population evolution. Option number 2 is correct.

Step-by-step explanation:

When considering the role of mutations on allele frequency changes through time, the occurrence of back mutations (that fix the mutation) are often ignored because the back mutation rate is so low. Back mutations are when a nucleotide pair of a DNA sequence that has experienced a point mutation is mutated again to restore the original sequence.

While it is possible for back mutations to occur, it's rare enough that they generally have a negligible effect on the overall allele frequency in a population. This rarity is due to the already low mutation rate, and the chances of the same gene mutating back to its original form are even lower. Therefore, it's not problematic to overlook back mutations when analyzing allele frequency changes.