Humans are more closely related to hogs than hogs are to guinea pigs.
Explanation:
The difference in the amino acid sequence of a protein is used to know the  relation between organism i.e. how closely they are related.
It is known that proteins are the result of DNA sequence ie genes of the organism.
The gene or protein is compared between organisms to understand the evolutionary evidence and similarities between them.
The less is the difference the more is the two organisms closely related as in the case of hog and human which have only 1 amino acid difference in their insulin enzyme. While guinea pig is having  a difference of 17 amino acids so it is expected to be distantly related.
These relations helps the scientist to resolve the issues of crisis say insulin. They zero out the possibility of extracting the enzyme genes of possible organism and increase the yield.
