Correct option is A
The molecular clock hypothesis proposed by Zuckerkandl and Pauling (1962) suggests that the rate at which molecular sequences (like DNA and proteins) evolve can be used as a "clock" to estimate the time of divergence between species. According to the hypothesis, DNA and protein sequences evolve at a relatively constant rate over time, making them useful for dating evolutionary events. The other statements are incorrect because they misinterpret the molecular clock concept.
Information Booster:
The molecular clock hypothesis assumes that mutations accumulate at a relatively constant rate over time, making molecular sequences a useful tool for estimating the divergence between species.
Amino acid and protein sequences evolve at rates that can be influenced by various evolutionary pressures, but the clock hypothesis generally treats DNA and protein evolution as relatively constant.
The concept of the molecular clock is supported by the fact that, in the absence of strong selective pressures, the number of mutations in a lineage can be used to estimate the time of divergence from a common ancestor.
Additional Knowledge:
DNA sequences (option 2) evolve at rates that can be variable due to various factors, such as selection pressures and the function of specific genes, and do not evolve strictly at slower rates compared to proteins.
Amino acid sequences (option 3) do not evolve stochastically in the strict sense, as they are subject to selective pressures and evolutionary forces.
The claim that protein sequences do not evolve (option 4) is incorrect because protein sequences evolve, especially when DNA sequences evolve under normal conditions, as changes in DNA sequences can lead to changes in protein sequences.
