Molecular Clock and Mutation Rates

The video discusses the molecular clock hypothesis, which relates genetic differences between species to their divergence time. Based on Kimura's neutral theory, it explains that neutral mutations occur without affecting evolutionary fitness. The video provides evidence supporting the theory, such as higher synonymous mutations and faster evolution in pseudogenes. It also covers calibrating the molecular clock using fossils or geological events and demonstrates a formula for calculating divergence with an example problem.

What is the primary purpose of the molecular clock hypothesis?

• To measure the speed of chemical reactions

• To relate genetic differences between species over time

• To calculate the age of fossils

• To determine the lifespan of a species

According to Kimura's neutral theory, what happens to mutations that do not affect evolutionary fitness?

• They always provide an advantage

• They are neither favored nor disfavored by natural selection

• They are always favored by natural selection

• They are always eliminated by natural selection

What is the substitution rate according to Kimura's theory?

• The rate at which species evolve

• The rate at which new mutations occur

• The rate at which mutations are eliminated

• The rate at which a mutation is fixed

Which type of base substitution is more common according to the observations supporting the neutral theory?

• Non-synonymous base substitutions

• Synonymous base substitutions

• Harmful mutations

• Beneficial mutations

In which type of sequences is the mutation rate higher?

• Functional genes

• Mitochondrial DNA

• Coding sequences

• Non-coding sequences

What is the purpose of calibrating the molecular clock?

• To calculate the age of the Earth

• To determine the exact genetic sequence of a species

• To measure the speed of DNA replication

• To find the time over which genetic divergence occurred

Which method can be used to calibrate the molecular clock?

• Measuring atmospheric pressure

• Analyzing fossil records

• Observing animal behavior

• Using the speed of light

What does the formula R = D / 2T represent?

• The speed of protein synthesis

• The age of a fossil

• The rate of nucleotide substitution

• The rate of DNA replication

In the formula R = D / 2T, what does 'D' stand for?

• The number of species

• The proportion of base pairs that differ

• The rate of mutation

• The time in million years

In the example problem, what is the estimated rate of divergence per base pair?

• 0.0045 per million years

• 0.0035 per million years

• 0.0025 per million years

• 0.0015 per million years