If a protein common to two different species has many amino acid differences, what can be concluded?

We can determine (or at least make a good educated guess) how similar or different two species are from one another on the evolutionary timeline based on the number of base pair differences in the DNA for a given protein between the two species.

Given that there are a lot of amino acid differences in this instance, a lot of the corresponding base pairs would also be different. This indicates that the species have undergone significant evolutionary differences, leading us to conclude that the species diverged relatively recently on the evolutionary timeline.

I hope that was helpful.

If a protein common to two different species has many amino acid differences, it can be concluded that the protein has undergone significant evolutionary divergence between the two species. This divergence could be due to genetic mutations, natural selection, or other evolutionary forces acting over time.