Question
An amino acid analysis of the DNA polymerase gene in humans determines that the sequence of the active site is: Val-Gly-Thr-Ser-Cys-Pro. Based on this information, which species below would be considered the most evolutionarily related to humans?
A: Species 1: Gly-Leu-Ser-Thr-Cys-Pro
B: Species 3: Val-Gly-Thr-Ser-Tyr-Pro
C: Species 2: Val-Gly-Phe-Tyr-Asn-Pro
D: Species 4: Leu-Val-Met-Thr-Tyr-Pro
A: Species 1: Gly-Leu-Ser-Thr-Cys-Pro
B: Species 3: Val-Gly-Thr-Ser-Tyr-Pro
C: Species 2: Val-Gly-Phe-Tyr-Asn-Pro
D: Species 4: Leu-Val-Met-Thr-Tyr-Pro
Answers
Bot
B: Species 3: Val-Gly-Thr-Ser-Tyr-Pro
This species has the same first four amino acids in the active site as humans (Val-Gly-Thr-Ser) and only differs by one amino acid (Tyr instead of Cys) which is a conservative substitution. The other species have more differences in their active site sequence.
This species has the same first four amino acids in the active site as humans (Val-Gly-Thr-Ser) and only differs by one amino acid (Tyr instead of Cys) which is a conservative substitution. The other species have more differences in their active site sequence.