Population Genetics

Question 1

Hemochromatosis is popular in what population

Answer 1

celtics

Question 2

sickle cell disease is popular in what population

Answer 2

Africans

Question 3

alpha and beta thalassemia is popular in what population

Answer 3

those with endemic malaria

Question 4

cystic fibrosis is popular in what population

Answer 4

Northern European

Question 5

Tay Sachs is popular in what population

Answer 5

Ashkenazi Jews

Question 6

A man who has a sister with PKU marries a woman from a population where the incidence of PKU is 1/10,000. What is the risk to their children?

Answer 6

1/300

Question 7

The incidence of PKU in a particular population is 1/10,000. What is the probability of finding a carrier of a PKU disease allele in this population?

Answer 7

1/50

Question 8

Bill’s sister has PKU. Jen’s niece has PKU. Incidence of PKU in the population is 1/10,000. What is the risk that Bill and Jen will have a baby with PKU?

Answer 8

1/12

Question 9

incidence of heterozygous carrier is ______ than incidence of affected homozygotes

Answer 9

much higher

Question 10

The disease allele frequency for PKU is 1/300 in a specific population. The predicted incidence of PKU in this population is

Answer 10

1/90,000

Question 11

The probability of being a carrier of a disease allele for PKU is 1/20 in a specific population. The estimated incidence of PKU in this population is

Answer 11

1/1600

Question 12

if incidence in hemophilia A is 1/10,000, what is the incidence of the disease in males

Answer 12

1/10000 because they are hemizygous

Question 13

what is incidence of hemophilia A (q=1/10,000) in heterozygous and homozygous females

Answer 13

homozygous : 1/10^8

heterozygous: 1/5,000

Question 14

assumptions of hardy weinberg equilibrium

Answer 14

population is large
random mating (so no consanguinity or mate selection based on genotype)
no new mutation in the population
no migration of individuals into the population

Question 15

what are factors that cause genetic variation in population AKA factors resulting in departure from Hardy Weinberg

Answer 15

new mutation, genetic drift, consanguinity, natural selection

Question 16

some genetic loci show high mutation rates which leads to…

Answer 16

steady increase in the proportion of mutant alleles in the population

Question 17

some mutations show low reproductive fitness which leads to ..

Answer 17

loss of mutant alleles

Question 18

what happens to the mutations that have a balance between high mutation rates and low reproductive fitness

Answer 18

maintain mutant gene frequency in population

Question 19

advantage of being sickle cell carrier

Answer 19

heterozygote advantage against malaria falciparum - malaria causes the RBCs to rupture thereby reducing the ability of plasmodium to reproduce

Question 20

other than HbS allele, what is also protective against malaria

Answer 20

beta thalassemia

Question 21

what does natural selection do?

Answer 21

increase the frequency of alleles that promote survival and decrease the frequency of those that reduce survival

Question 22

why do Tay Sachs and Turners represent zero fitness

Answer 22

Tay Sachs - death during infancy

Turners - infertility

Question 23

type of fitness in those with huntingtons and PKU

Answer 23

huntingtons - average fitness; disease does not manifest until after individual has had children

PKU - if properly treated, normal fitness but if left untreated leads to reduced fitness due to intellectual disability and medical concerns

Question 24

who does genetic drift affect the most

Answer 24

small populations because fluctuations can lead to fixing or extinguishing of an allele

Question 25

what is founders effect

Answer 25

when a person who is recessive for a mutant allele moves into a small population without the mutant allele. Over time and with reproduction, the mutant allele spreads eventually leading to manifestation of the disease in homozygous individuals

Question 26

common in Ashkenazi Jews

Answer 26

Gauchers, Tay Sachs, Canavan disease

Question 27

common in Amish from Holmes County, Ohio

Answer 27

Ataxia telangiectasia and cystic fibrosis

Question 28

common in Hopi indians of Arizona

Answer 28

albinism

Question 29

In a specific population, alkaptonuria, an autosomal recessive disease, has an incidence of 1/10,000. A carrier female marries an unrelated person from the population. What is the risk that they will have a child with alkaptonuria?

Answer 29

1/200

Question 30

child of first cousins have what ratio of having disease

Answer 30

1/16

Question 31

child of second cousins have what ratio of having disease

Answer 31

1/32

Question 32

are disease alleles identical in person who is a product of consanguinity

Answer 32

yeah

Question 33

You are consulted by a couple, Abby and Andrew, who tell you that Abby’s sister Anna, has Hurler syndrome (a mucopolysaccharidosis) and that they are concerned that they themselves might have a child with the same disorder. Hurler syndrome is an autosomal recessive condition with a population incidence of about 1 in 90,000 in your community. If Abby and Andrew are not consanguineous, what is the risk that their first child will have Hurler syndrome?

Answer 33

1/900

Question 34

You are consulted by a couple, Abby and Andrew, who tell you that Abby’s sister Anna, has Hurler syndrome (a mucopolysaccharidosis) and that they are concerned that they themselves might have a child with the same disorder. Hurler syndrome is an autosomal recessive condition with a population incidence of about 1 in 90,000 in your community. What is the risk if they are first cousins?

Answer 34

1/24

Question 35

Prevalence of a mutant allele in high frequency in a population, look for causes of the prevalence of the mutant allele such as….

Answer 35

geographical isolation, natural selection (heterozygote advantage and improved fitness), consanguinity, high mutation rate of the genes