EE4

Question 1

What is an adaption?

Answer 1

A characteristic that enhances the survival or reproductivity relative to other characters

Question 2

What is relative fittness?

Answer 2

Average number of surviving progeny of a particular genotype compared with average number of surviving progeny of competing genotypes after single generation
1 genotype is normalised at w=1

Question 3

What is fittness?

Answer 3

The ability to survive and reproduce

Average fecundity x Average Survivorship

Question 4

What affects fixation and why?

Answer 4

Whether it is selected for or not.

natural selection is faster than genetic drift as it increases fittness of a population.

Question 5

What is the Duffy Null Mutation?

Answer 5

Plasmodium Vivax

• requires DARC protein on RBC to enter and infect the cells
• Duffy Null mutation results in loss of DARC expression.
• Duffy Null phenotype is therefore resistent to vivax malaria
• fixed for subsahharan Africa

Question 6

What is MHC?

Answer 6

Major Histocompatibility Complex
Set of cell surface molecules encoded by large gene family
Controls major part of immune system
major role is to bind to peptide fragments derived from pathogens and display on CS for recognition
the more polymorphic - the more antigens can be recognised
for some alleles can be more related to chimps than humans

Question 7

What is:
Stabilising Selection
Disruptive Selection
Directional Selection

Answer 7

Stabilising selection is selection against extremes
Disruptive selection is selection against mean
Directional Selection is selection against an extreme