Lecture 28

Question 1

Ecological genetics:

Answer 1

• Understanding genes in natural environments
• Adaptation and how organisms undergo adaption
• Survival and reproduction
• ## Evolutionary processes in nature and the extent to which species are able to adapt

Question 2

Quantitative genetic diversity:

Answer 2

• Traits associated with many genes

eg) size is measured on a quantitative scale and is associated with multiple genes and is under selection

Question 3

Allozyme variation in butterflies and PGI:

Answer 3

• PGI is an allozyme with different forms across the population
• The gene is protein coding
• Heterozygotes are more active at cooler morning temperatures
• The quantitative behaviour is flight behaviour
  This gene has a big effect on flight behaviour.

Question 4

Early flight provides a reproductive fitness advantage

Answer 4

• Functional studies show that PGI heterozygotes fly better in the cold
• 3/4 heterozygotes perform better, in the field and in the lab
• This will maintain variation in the population

Question 5

PGI variation is ubiquitous in insects flight ability:

Answer 5

• This allows extension from gene to trait

- Balancing selection is maintained here

Question 6

Chromosomal rearrangement:

Answer 6

• Inversions
• polymorphisms for chromosomal rearrangements such as inversions exist
• Inversions can be studied

Question 7

There are many example of genetic polymorphisms under selection:

Answer 7

• Several allozymes
• Chromosomal rearrangements
• Insertions/deltions
• SNPs

Question 8

Multiple polymorphism scans allow us to determine how adaptable a particular genome is:

Answer 8

• Carried out across time or (usually) across space
• Ideally this will be replicated across time or space to determine a difference
• Fst analyses can be used to identify outliers and loci with very large Fsts are looked for

Question 9

Arabis alpina is a plant studied in relation to elevation:

Answer 9

• Fst was studied and two peaks were found
• This means there are two genomic sequences associated with elevation
• What genes are these? How do they effect the polymorphism?

Question 10

Genome Wide scans are

Answer 10

• Markers are available across entire genomes
• They may involve re-sequencing or markers such as RADs
• It is important to separate population processes, such as admixture
• Functional analyses of identified polymorphisms are needed
• This identification does not indicate how important a polymorphism is for a trait without additional functional analysis
• How many other genes are involved and what fraction of the variation in the trait is determined by that particular gene?