Chapter 26, Problem 26.5CR

Summary Introduction

To describe: The assumptions and limitations of the molecular clock.

Concept introduction: It is important to understand the relationship among organisms to explore their evolutionary history. Some genes evolve at a constant rate which will be helpful to get evolutionary information. However, a gene can evolve at different rates depending on the environment they live. The molecular clock is an approach to measure the time of evolutionary change. The calculation of a molecular clock of a gene can be possible through study of fossil records and plotting the evolution rate taken by a gene. The evolution time point will be represented by genetic differences in terms of nucleotides, codons or amino acids.