lecture 7 - evolution and population genetics

Question 1

What is evolution?

Answer 1

There are many definitions, e.g.
• the process by which different kinds of living
organism are believed to have developed from
earlier forms during the history of the earth
(Oxford English Dictionary)
• change in the gene pool of a population from
generation to generation by such processes as
mutation, natural selection, and genetic drift
(dictionary.com)
The simplest and most general:
• A change in allele or genotype frequencies

Question 2

Why is evolution important?

Answer 2

• All forms of life and biodiversity exist due to
evolutionary processes
• Evolution is an ongoing process, that affects all
populations and can lead to significant changes
over “ecological” timescales
• Evolution occurs in economically and medically
important organisms, e.g. farm animals, antibiotic
resistance in pathogens, humans.

Question 3

What is population genetics?

Answer 3

• Study of patterns of genetic variation and
of the mechanism of evolution, i.e. of allele
and genotype frequency changes
• Processes:
• Mutation and Recombination
• Genetic drift
• Selection
• Gene flow
• Non-random mating

Question 4

What is an adaption?

Answer 4

a consequence of selection:
a feature that has a beneficial function and has
become prevalent or is maintained in a population
or species because of natural selection for that
function

Question 5

What is the importance of mutations?

Answer 5

All genetic variation is originally due to mutations,
no evolution without mutations!
• Mutations are rare
• Mutations can be
• somatic or in the germline
• advantageous, neutral or deleterious
• Population genetics:
• Fate of mutations
• The mutation itself does not change allele
frequencies to a significant degree, other processes
need to act.

Question 6

What is genetic drift?

Answer 6

Random change of allele frequencies from

generation to generation