Estimating risk of inherited genetics

Question 1

Define fitness

Answer 1

means the relative ability of organisms to survive and pass on genes

Question 2

What effects fitness

Answer 2

alleles

Question 3

What do genotype frequencies calculate

Answer 3

How many genotypes in the population

Question 4

How do we calculate genotype frequency

Answer 4

the number of people with that genotype divided by the number of people overall

Question 5

What must an allele frequency always add up to

Answer 5

1

Question 6

What is the genotype frequency equation for

AA : Aa : aa

Answer 6

p2 : 2pq : q2

Question 7

What is the allele frequency of A:a

Answer 7

p:q

Question 8

What do the allele frequency and genotype frequency of the Hardy-Weinberg equilibrium prove to us

Answer 8

Relative frequencies always remain constant therefore dominant alleles don’t become more common

Question 9

What is an idea population that will fit withHardy-Weinberg equilibrium

Answer 9

Mutation can be ignored
Migration is negligible (No gene flow)
Mating is random
No selective pressure
Population size is large
Allele frequencies are equal in the sexes

Question 10

What can increases the proportion of new alleles

Answer 10

Mutations

Migrations

Question 11

What can increase mutant alleles

Answer 11

Non random mating

Question 12

What are two forms of nonrandom mating

Answer 12

Assortative mating - of shared characteristics

Consanguinity - between relatives

Question 13

Define natural selection

Answer 13

A gradual process by which biological traits become either more or less common in a population

Question 14

What natural selection increases reproductive fitness the prevalence of adaptive traits and it gives a heterozygote advantage

Answer 14

Postive selection

Question 15

What does negative selection reduce

Answer 15

reproductive fitness
prevalence of traits
reduction of mutant allele

Question 16

Give 3 examples of heterozygous advantages and there resistances

Answer 16

sickle cell anaemia - malaria
cystic fibrosis - cholera/typhoid
Glucose 6 phosphate dehydrogenase deficiency - malaria

Question 17

What can small population cause

Answer 17

genetic drift

founder effect

Question 18

Define genetic drift

Answer 18

Statistical drift of gene frequencies due to chance or random events leading to the variation in the relative frequency of different genotypes in a small population

Question 19

Define founder effect

Answer 19

The reduction in genetic variation that results when a small subset of a large population is used to establish a new colony

Question 20

What is the result of the founder effect

Answer 20

limits genetic variation

Question 21

What is applications of HWE

Answer 21

Useful for calculating risk in genetic counselling

Useful for planning population based carrier screening programmes

Question 22

To calculate a carrier frequency what do you need to find out of ratio p² : 2pq : q²

Answer 22

2pq - heterozygote

Question 23

How do you work out carrier frequency,

Answer 23

well you calculate q from statistic  
p+q= 1, 
calculate p= 1-q, 
Now you have p and q 
2 x p x q 
=2pq