Estimating Risk of Inherited Genetic Disorder

Question 1

Fitness

Answer 1

The ability of organisms to survive long enough to pass on their genes.

Question 2

Selective pressure

Answer 2

Any reason for organisms with certain phenotypes to have survival benefit or disadvantage. If selective pressures change; importance of different alleles may change.

Question 3

Alleles significance

Answer 3

Natural allele - no effect.
Deleterious allele - sometimes decreases fitness.
Advantageous allele - rarely increases fitness.

Question 4

Founder effect

Answer 4

The loss of genetic variation that occurs when a new population is established by a very small number of individuals from a larger population.

Question 5

Natural selection

Answer 5

A gradual process by which biological traits become more/less common in a population, driven by selective pressures.

Question 6

Negative selection

Answer 6

Reduces reproductive fitness by a gradual decrease in mutant allele.

Question 7

Positive selection

Answer 7

Increases fitness e.g. sickle cell anaemia and malaria.