Estimating Risk of Inherited Genetic Disease Flashcards Preview

Principles of Disease > Estimating Risk of Inherited Genetic Disease > Flashcards

Flashcards in Estimating Risk of Inherited Genetic Disease Deck (31)
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1
Q

Define fitness.

A

Relative ability of organisms to survive and pass on genes.

2
Q

How do neutral alleles affect fitness?

A

Not at all in most cases

3
Q

How do deleterious alleles affect fitness?

A

Sometimes decrease

4
Q

How do advantageous alleles affect fitness?

A

Rarely increase

5
Q

What affects the health of the population?

A

The frequency of alleles in the whole population.

6
Q

What is a genotype?

A

A gene with two alleles.

7
Q

What are the 3 genotypes?

A

AA
Aa
aa

8
Q

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

A

1.0

9
Q

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

A

p2 : 2pq : q2

10
Q

What is the constant relative frequency?

A

p:q

11
Q

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

A

No

12
Q

What are the 2 conditions of HWE?

A

Allele frequencies remain constant generation to generation.

Relative proportion of genotype frequencies remain constant generation to generation.

13
Q

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

A

1

14
Q

Should mutation be ignored for an ideal population?

A

Yes

15
Q

Should migration occur for an ideal population?

A

No

16
Q

Should mating be random in an ideal population?

A

Yes

17
Q

Should there be no selective pressure in an ideal population?

A

Yes

18
Q

Should the population size be small in an ideal population?

A

No

19
Q

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

A

No

20
Q

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

A

Introduction of new alleles which leads to hybrid population.

21
Q

What leads to an increase in mutant alleles?

A

Non-random mating

22
Q

What is assortative mating?

A

Choosing of partners due to shared characteristics.

23
Q

What is consanguinity?

A

Marriage between close blood relatives.

24
Q

What is natural selection?

A

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

25
Q

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

A

Reduces
Decreases
Reduction

26
Q

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

A

Increases
Increases
Advantage

27
Q

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

A

Small

28
Q

Define genetic drift.

A

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

29
Q

Define founder effect.

A

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

30
Q

What is polydactyly?

A

Extra fingers/toes

31
Q

What are the two applications of HWE?

A

Useful for calculating risk in genetic

Useful for planning population based carrier screening programmes