Lecture 17: Models and Measurement

Question 1

What are the benefits of studying population genetics?

Answer 1

It can help us understand the past, present and future of evolutionary potential

Question 2

What factors affect genetic diversity?

Answer 2

1. mutations
2. recombinations ( new combinations of existing mutations)
3. genetic drift (variations in the frequency of traits in offspring)
   gene flow (migration)
4. natural selection

Question 3

What are the different subgroups that natural selection can fall in when it comes to genetic diversity

Answer 3

Negative (purifying): the mutations that hinder fitness will be phased out

Positive (directional): mutations that benefit fitness will be kept

Selection Favouring: maintaining diversity

Question 4

What are the metrics of genetic variation?

Answer 4

Heterozygosity: fraction of individuals that have 2 different alleles present in a gene loci

Polymorphism:2 different phenotypic individuals belonging to the same species in the same population

Question 6

What Maintains genetic variation?

Answer 6

Mutation-section balance: less fit types are introduced due to mutation, which will be removed eventually due to natural selection

Selection-Maintaining: Heterozygote advantage where the allele chosen varies over time with frequency

Question 7

How do the 2 schools of population genetic variation differ?

Answer 7

The 2 schools differ based on ho much genetic variation occurs in natural populations

Question 8

Explain the difference between the classical and balance school

Answer 8

Classical school has negative selection that focuses on low heterozygosity and polymorphism with the wild type being the normal type.

Balance school focuses on high heterozygosity and polymorphism with a heterozygote advantage.
This is where selection favors diversity

Question 9

Early quantitative genetic evidence on genetic variation

Answer 9

focused on polygenic traits done through artificial selection.

Question 10

Results of the early experiments

Answer 10

Abundant genetic variation for polygenic traits but there was no information on polymorphism and heterozygosity

Question 11

Advantages of studies involving electrophoresis

Answer 11

Many loci can be examined
Heterozygotes can be identified
Variants can be examined