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Flashcards in Population Genetics Deck (35)
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1
Q

Hemochromatosis is popular in what population

A

celtics

2
Q

sickle cell disease is popular in what population

A

Africans

3
Q

alpha and beta thalassemia is popular in what population

A

those with endemic malaria

4
Q

cystic fibrosis is popular in what population

A

Northern European

5
Q

Tay Sachs is popular in what population

A

Ashkenazi Jews

6
Q

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?

A

1/300

7
Q

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?

A

1/50

8
Q

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?

A

1/12

9
Q

incidence of heterozygous carrier is ______ than incidence of affected homozygotes

A

much higher

10
Q

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

A

1/90,000

11
Q

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

A

1/1600

12
Q

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

A

1/10000 because they are hemizygous

13
Q

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

A

homozygous : 1/10^8

heterozygous: 1/5,000

14
Q

assumptions of hardy weinberg equilibrium

A

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

15
Q

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

A

new mutation, genetic drift, consanguinity, natural selection

16
Q

some genetic loci show high mutation rates which leads to…

A

steady increase in the proportion of mutant alleles in the population

17
Q

some mutations show low reproductive fitness which leads to ..

A

loss of mutant alleles

18
Q

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

A

maintain mutant gene frequency in population

19
Q

advantage of being sickle cell carrier

A

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

20
Q

other than HbS allele, what is also protective against malaria

A

beta thalassemia

21
Q

what does natural selection do?

A

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

22
Q

why do Tay Sachs and Turners represent zero fitness

A

Tay Sachs - death during infancy

Turners - infertility

23
Q

type of fitness in those with huntingtons and PKU

A

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

24
Q

who does genetic drift affect the most

A

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

25
Q

what is founders effect

A

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

26
Q

common in Ashkenazi Jews

A

Gauchers, Tay Sachs, Canavan disease

27
Q

common in Amish from Holmes County, Ohio

A

Ataxia telangiectasia and cystic fibrosis

28
Q

common in Hopi indians of Arizona

A

albinism

29
Q

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?

A

1/200

30
Q

child of first cousins have what ratio of having disease

A

1/16

31
Q

child of second cousins have what ratio of having disease

A

1/32

32
Q

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

A

yeah

33
Q

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?

A

1/900

34
Q

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?

A

1/24

35
Q

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

A

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