Which of the following would violate the assumptions of the molecular clock?
A) comparison of genes of a species that lives deep in the ocean with relatives that live on the surface and are exposed to strong mutation-inducing ultraviolet radiation
B) comparison of genes for homologous structures across many species
C) comparison of many genes in many species of insects that undergo metamorphosis
D) assuming that organisms in competitive environments have the same rate of mutation as those in noncompetitive environments

Question

Quizplus · Accepted Answer

The assumptions of the molecular clock include a constant rate of mutation and a random distribution of mutations. However, organisms living in different environments may experience different rates of mutation and different types of mutations, violating the assumption of a constant rate of mutation.

Answer: B 
 The molecular clock assumes that mutations occur randomly and affect all genes equally. However, genes for homologous structures may be under different selective pressures and may not mutate at a constant rate across all species, violating the assumption of a constant rate of mutation.

Answer: C 
 The molecular clock assumes a constant rate of mutation across all genes and species. However, the process of metamorphosis in insects involves significant changes in gene expression and metabolism, which may affect the rate of mutation, violating the assumption of a constant rate of mutation.

Answer: D 
 The molecular clock assumes a constant rate of mutation across all genes and species. However, organisms in competitive environments may experience different rates of mutation (e.g. due to increased DNA damage from stress or exposure to toxins) than those in noncompetitive environments, violating the assumption of a constant rate of mutation.

Which of the Following Would Violate the Assumptions of the Molecular