2: Multilevel Selection

Question 1

Describe multi level selection in the context of Mitochondrial ‘petite’ mutations in yeast

Answer 1

• In yeast, ‘petite’ colonies can develop (with defective mitochondria, severe metabolic problems = poor growth)
• These colonies form because petite mutations are large deletions = faster replication of their mt genome, which outcompetes other mt within cell (mutation favoured at mitchondrial level)
  = Genomic conflict: mutation is selected for at mt level but against at cell level (bc impare cell growth)

Question 2

Describe Transposable elements

Answer 2

• DNA transposons (cut-and-paste DNA containing the transposase enzyme around the genome)
• Large amount of genome expansion is explained by TE proliferation.

Costs:
- having more DNA (time to replicate)
- Main cost is due to TEs interruping the function of other cells

Question 3

Selfish genetic elements are passed on to the next generation at a —— rate than expected under normal —— inheritance

Answer 3

higher
Mendelian

Question 4

How do Segregation distorters cause meiotic drive?

Answer 4

They can drive meiosis away from equality by distorting segregation to favour certain alleles causing meiotic drive

e.g. Sex-Ratio (SR) in Drosophila.

Question 5

Describe how group selection might work on a population level

Answer 5

Used to explain the evolution of altruism:
- Altrusim = greater survival of the group
- Compared to selfish groups

Question 6

Describe kin selection theory

Answer 6

• Uses inclusive fitness to explain traits that are anatgonsistic to selection at the individual level (e.g altrusim)
• Inclusive fitness = direct fitness (personal sitness gains) + indirect fitness (extra fitness gained from relatives)

Question 7

How is r different in haplodiploid eusocial systems

Answer 7

• Males are haploid (unfertilised eggs), females diploid
• So… sisters share 3/4 of genes (r = 0.75)
• So… siseters are more closely related to one another than to their own offspring (r = 0.5)