Estimating Risk of Inherited Genetic Disease

Question 1

Define fitness.

Answer 1

Relative ability of organisms to survive and pass on genes.

Question 2

How do neutral alleles affect fitness?

Answer 2

Not at all in most cases

Question 3

How do deleterious alleles affect fitness?

Answer 3

Sometimes decrease

Question 4

How do advantageous alleles affect fitness?

Answer 4

Rarely increase

Question 5

What affects the health of the population?

Answer 5

The frequency of alleles in the whole population.

Question 6

What is a genotype?

Answer 6

A gene with two alleles.

Question 7

What are the 3 genotypes?

Answer 7

AA
Aa
aa

Question 8

Frequency of A (p) + Frequency of a (q) =

Answer 8

1.0

Question 9

What is the ratio in terms of p and q for a punnet square of genotypes Aa and Aa?

Answer 9

p2 : 2pq : q2

Question 10

What is the constant relative frequency?

Answer 10

p:q

Question 11

Do dominant conditions become more common at the expense of recessive ones?

Answer 11

No

Question 12

What are the 2 conditions of HWE?

Answer 12

Allele frequencies remain constant generation to generation.

Relative proportion of genotype frequencies remain constant generation to generation.

Question 13

What will the allele frequency be no matter what in HWE?

Answer 13

1

Question 14

Should mutation be ignored for an ideal population?

Answer 14

Yes

Question 15

Should migration occur for an ideal population?

Answer 15

No

Question 16

Should mating be random in an ideal population?

Answer 16

Yes

Question 17

Should there be no selective pressure in an ideal population?

Answer 17

Yes

Question 18

Should the population size be small in an ideal population?

Answer 18

No

Question 19

Should allele frequencies by different in the sexes in an ideal population?

Answer 19

No

Question 20

What happens to alleles as a result of migration or intermarriage?

Answer 20

Introduction of new alleles which leads to hybrid population.

Question 21

What leads to an increase in mutant alleles?

Answer 21

Non-random mating

Question 22

What is assortative mating?

Answer 22

Choosing of partners due to shared characteristics.

Question 23

What is consanguinity?

Answer 23

Marriage between close blood relatives.

Question 24

What is natural selection?

Answer 24

Gradual process by which biological traits become either more or less common in a population.

Question 25

Negative selection:
______ reproductive fitness.
______ the prevalence of traits.
Leads to gradual ______ of mutant allele.

Answer 25

Reduces
Decreases
Reduction

Question 26

Positive selection:
______ reproductive fitness.
______ the prevalence of adaptive traits.
Heterozygote ______.

Answer 26

Increases
Increases
Advantage

Question 27

What size of populations can exhibit genetic drift and founder effect?

Answer 27

Small

Question 28

Define genetic drift.

Answer 28

Random increases of one allele transmitted to high proportion of offspring by chance.

Question 29

Define founder effect.

Answer 29

Reduction in genetic variation when small subset of population establishes a new colony.

Question 30

What is polydactyly?

Answer 30

Extra fingers/toes

Question 31

What are the two applications of HWE?

Answer 31

Useful for calculating risk in genetic

Useful for planning population based carrier screening programmes