Question

Biologists are studying two species whose DNA is known to differ by 10%. Knowledge of which of the following would be least important in calibrating a molecular clock to determine how rapidly evolution has proceeded with these two species?

A. a geological event that separated the species at a particular time.
B. the function of each of these regions of DNA
C. the fossil record of these two species
D. the time of divergence of closely related species

Answer 1

The correct answer is option b. For calibrating a molecular clock, the function of the DNA regions is the least relevant among the given options. Molecular clocks rely on the rate of mutation, not on the functions of the genetic regions.

Step-by-step explanation:

Molecular clocks are a technique used in biology to estimate the time of divergence between two species by analyzing the differences in their DNA sequences. The most irrelevant information for calibrating a molecular clock, among the options provided, would be B. the function of each of these regions of DNA. This is because molecular clocks are based on the accumulation of neutral mutations that do not necessarily affect the function of the DNA regions. Instead, they are based on a consistent mutation rate over time.

Understanding the time of a geological event that separated species (A), the fossil record of the species (C), and the time of divergence of closely related species (D) are all crucial for calibrating a molecular clock. These factors help scientists determine the baseline rate of mutations or confirm the divergence times predicted by molecular clocks.