Question

When two genes from two different people are sequenced and aligned, it is discovered that there are multiple sequence differences in the coding segment DNA level. However, when the proteins formed by the genes have their amino acids sequenced, there is no difference observed between the two. What is the most likely explanation for this observation?

Mutations at the DNA level are not reflected in proteins produced.

The mutations lie at locations where they don't affect protein sequence due to degeneracy of the genetic code.

The mutations are corrected at the protein level after translation has occurred.

The mutations are repaired at the mRNA level after transcription has occurred, but before translation.

RNA processing removes the different segments from the mRNA molecules of each person prior to translation.

Answer 1

Second options

If the mutations are present in the third base of a codon, then due to wobble nature of third base, same amino acid is coded.

For example,

For amino acid alanine, there can be 4 codons, GCA, GCG, GCC, GCU.

For amino acid cystine, there can be 2 codons, UGU and UGC.

So, if you look at the genetic code table, you will see that for most of the amino acids, more than one codons are there. So, this type of mutation (called as silent mutation), is present in DNA but due to affect the type of amino acid being formes due to degeneracy of codons.

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