Hemochromatosis is popular in what population
celtics
sickle cell disease is popular in what population
Africans
alpha and beta thalassemia is popular in what population
those with endemic malaria
cystic fibrosis is popular in what population
Northern European
Tay Sachs is popular in what population
Ashkenazi Jews
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?
1/300
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?
1/50
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?
1/12
incidence of heterozygous carrier is ______ than incidence of affected homozygotes
much higher
The disease allele frequency for PKU is 1/300 in a specific population. The predicted incidence of PKU in this population is
1/90,000
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
1/1600
if incidence in hemophilia A is 1/10,000, what is the incidence of the disease in males
1/10000 because they are hemizygous
what is incidence of hemophilia A (q=1/10,000) in heterozygous and homozygous females
homozygous : 1/10^8
heterozygous: 1/5,000
assumptions of hardy weinberg equilibrium
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
what are factors that cause genetic variation in population AKA factors resulting in departure from Hardy Weinberg
new mutation, genetic drift, consanguinity, natural selection
some genetic loci show high mutation rates which leads to…
steady increase in the proportion of mutant alleles in the population
some mutations show low reproductive fitness which leads to ..
loss of mutant alleles
what happens to the mutations that have a balance between high mutation rates and low reproductive fitness
maintain mutant gene frequency in population
advantage of being sickle cell carrier
heterozygote advantage against malaria falciparum - malaria causes the RBCs to rupture thereby reducing the ability of plasmodium to reproduce
other than HbS allele, what is also protective against malaria
beta thalassemia
what does natural selection do?
increase the frequency of alleles that promote survival and decrease the frequency of those that reduce survival
why do Tay Sachs and Turners represent zero fitness
Tay Sachs - death during infancy
Turners - infertility
type of fitness in those with huntingtons and PKU
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
who does genetic drift affect the most
small populations because fluctuations can lead to fixing or extinguishing of an allele
what is founders effect
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
common in Ashkenazi Jews
Gauchers, Tay Sachs, Canavan disease
common in Amish from Holmes County, Ohio
Ataxia telangiectasia and cystic fibrosis
common in Hopi indians of Arizona
albinism
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?
1/200
child of first cousins have what ratio of having disease
1/16
child of second cousins have what ratio of having disease
1/32
are disease alleles identical in person who is a product of consanguinity
yeah
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?
1/900
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?
1/24
Prevalence of a mutant allele in high frequency in a population, look for causes of the prevalence of the mutant allele such as….
geographical isolation, natural selection (heterozygote advantage and improved fitness), consanguinity, high mutation rate of the genes