Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Semester 5 FSNM Exam 9 > Genetics 2 > Flashcards

Genetics 2 Flashcards

1
Q

Prevalence of multifactorial diseases

A

60% of the population

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Prevalence of single gene disorders

A

2% of the population

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Prevalence of chromosomal and genomic disorders

A

0.38% of the population

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Quantitative trait is defined as

A

Something that can be measured

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Quantitative trait - usually determined by

A

many genes

Alleles can be contributing or noncontributing to the trait

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

In multifactorial diseases, the quantitative trait is

A

Liability or disease

The liability to the disorder is what you are measuring

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Multifactorial diseases are described by what model

A

The threshold model

Many genes and environmental factors are involved

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Threshold of liability

A

Everyone has liability - might be different for M and F

The lower the threshold, the more affected by the disease you are

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

If a multifactorial disease is more common in M it means what about their threshold

A

It is lower (so they have more liability/disease)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Implications of the threshold model - each birth of an affected child does what

A

Each birth of an affected child changes the risk analysis
Means that between the parents there are enough contributing alleles to cause disease
Birth of another affected child seems more likely

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Implications of the threshold model - Birth of a child of the less affected sex does what

A

Increased the risk even more

Between the parents there are enough contributing alleles to cross a higher threshold of liability

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Implications of the threshold model - in own words

A

If parents have one affected child, they now belong to a different population - when a child with a disorder is born, the curve is shifted so the chances of having another affected child increase (threshold decreases)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Pyloric stenosis - more common in who

A

boys

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Pyloric stenosis - Threshold for parents with an affected boy vs. threshold for parents with an affected girl

A

Threshold for the parents with the affected boy is lower (so liability is larger)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Pyloric stenosis - Risk for parents with an affected boy vs. an affected girl

A

Risk with an affected girl is higher because there are more alleles between parents because the threshold was higher

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Pyloric stenosis - what are the scenarios

A

Higher risk
Lower risk
Higher threshold
Lower threshold

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Pyloric stenosis - Recurrence risk for a family with an affected girl

A

Always lower than having a boy because girls have a higher threshold

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Pyloric stenosis - males need fewer contributing alleles to express the disease than females (their threshold is lower) so a family with an affected female proband

A

has more contributing alleles than a family with an affected male proband

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What is an example of a multifactorial disease that is more common in girls

A

Hip dysplasia - so if you have a boy with hip dysplasia, the risk is much higher for the next generation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Multifactorial diseases - environmenral and genetic contributions

A

All multifactorial diseases have environmental and genetic components

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

How do we dissect or quantify the environmental vs. genetic contributions

A

Observe concordance and discordance with twin and adoption studies

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Dissecting environmental and genetic contributions - concordance

A

The pair has the same trait

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Dissecting environmental and genetic contributions - discordance

A

the pair is different from one another

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Dissecting environmental and genetic contributions - twin studies

A

Compare concordance in pairs of monozygotic and dizygotic twins

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

Dissecting environmental and genetic contributions - adoption studies

A

Compare adopted children to their biological and adopted parents

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

Twin studies - monozygotic twins vs. dizygotic twins

A

Mono - genetically identical

Dizygotic - share 50% of their genes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

Twin studies - what is the assumption that is made with MZ and DZ twins

A

They grow up under similar circumstances

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

Twin studies - if concordance in MZ is higher than in DZ, then the trait has what

A

Higher genetic component

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

Heritability can be estimated as (H^2) =

A

(concordance MZ - concordance DZ) x 2

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

The higher the heritability, the higher the

A

genetic component

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

Mapping of complex traits - what is it

A

Model free linkage analysis through association studies
Analyze whole genome for polymorphisms (sequence deviations) in affected families
Looking for polymorphisms that are associated with disease

32
Q

Mapping of complex traits - what is the goal

A

Trying to find a polymorphism in a pedigree that correlates with a disorder
Tracking inheritance of polymorphism and trying to correlate it with inheritance of the disease

33
Q

Polymorphism is what

A

You don’t know what gene it is or what it does but if the nucleotide of the polymorphism is associated with a disease, the gene that causes the disease should be close by because it tends to transmit together with the polymorphism

34
Q

Genome wide association studies

A

Compare SNPs in patients and controls
Calculate odds ration for each SNP
Find SNPs that are strongly associated with the disease

35
Q

Genome wide association studies - examble

A

Measured trait of circulation in skin and mapped polymorphism to circulation in skin
Then look to see at what locust you see a strong correlation with a phenotype and polymorphism

36
Q

Risk analysis - relative risk ratio is what

A

a way to describe multifactorial diseases

37
Q

What does a relative risk ratio of 1.5 for siblings mean

A

Siblings of affected individuals are 1.5 times as likely to develop the disease than the general population

38
Q

Disease association of allele - in multifactorial diseases

A

there is a correlation between a particular allele and disease
Relative risk is a way to describe the disease association of an allele

39
Q

Relative risk describes what

A

how much more likely a carrier of an allel is to develop the disease than a non carrier

40
Q

If the relative risk for allele X is 1.5 this means you tell your pt that

A

If we find that you are a carrier of allele X, your risk is 1.5 times the risk of a non carrier

41
Q

Relative risk ratio vs. Relative risk

A

Ratio - no genetics, all family hx and pedigree

RR - molecular genetics

42
Q

Characteristic inheritance of multifactorial diseases - what do they follow

A

NOT mendelian

They are determined by the threshold model

43
Q

Characteristic inheritance of multifactorial diseases - Multifactorial diseases show ____ ____

A

Familial aggregation - it does run in families

44
Q

Characteristic inheritance of multifactorial diseases - multifactorial diseases frequently show what kind of penetrance

A

Incomplete penetrance

Because it has an environmental component that can be modified

45
Q

Characteristic inheritance of multifactorial diseases - disease is much more common among who

A

close relatives of proband than it is among less closely related persons

46
Q

Characteristic inheritance of multifactorial diseases - Recurrence vs. Occurence

A

Threshold model explains why they recurrence risk is higher than the occurrence risk
The more affected children that are born to a couple, the higher the assumed number of contributing alleles in the parent generation - every time an affected child is born into a family, the recurrence risk has to be corrected upwards

47
Q

HLA Haplotypes and Diabetes - HLA haplotypes are associated with what

A

Autoimmune disorders

48
Q

HLA Haplotypes are inherited how

A

as blocks

they are codominant

49
Q

HLA haplotypes - variation in the HLA region accounts for what percent of genetic risk for T1D

A

40%

50
Q

HLA haplotype - which genetic variation affects risk for T1D

A

DR-DQ haplotypes

51
Q

HLA haplotype - susceptibility alleles

A

The DR-DQ haplotypes hat increase the risk for T1D

52
Q

HLA haplotype - protective alleles

A

The DR-DQ haplotypes that decrease the risk for T1D

53
Q

Population genetics - Polymorphic means what

A

an allele present in more than 1% of the population is called polymorphic

54
Q

Population genetics - polymorphisms - which genes have a high degree of polymorphism

A

HLA haplotypes

55
Q

Population genetics - polymorphisms - which genes are non polymorphic

A

Histones

56
Q

Population genetics - polymorphisms - Positive thing about HLA haplotypes (with high degree of polymorphism)

A

Good because everyone has a different resistance

57
Q

Population genetics - non polymorphic like the histones - how do they become non polymorphic

A

Streamlined so much that any mutation in the gene will compromise the function and be incompatible with life

58
Q

The hardy-weinberg principle

A

Hardy and Weinberg developed a simple model for the distribution of alleles in a population

59
Q

The HW principles - The model makes what four assumptions

A

The population in large
All genotypes have the same fitness
Mating is random
No influx or efflux of alleles from the gene pool

60
Q

HW principles - The model predicts that allele frequencies __ change over time

A

WILL NOT change over time

A rare allele right now will still be a rare allele 100 years from now

61
Q

The HW principle - the equations allow to calculate what

A

Allele and carrier frequencies - make connections between the gene pool and the population

62
Q

The reality - Genetic drift

A

Populations can be small and rare alleles can be lost by chance

63
Q

The reality - Selection

A

Selection selects against mutant alleles

Homozygoud mutant have reduced fitness, so then alleles disappear from the population

64
Q

The reality - Assortative mating

A

People who are genetically similar mate (homozygous) - and then you still have the same number of mutant alleles in the pool, but the distribution has changed and
Assorative mating increases the amount of homozygosity in a population

65
Q

The reality - Bottleneck and Recovery

A

Bottleneck event where some catastrophic event wipes out most of the population - often heterozygotes are the ones that survive - and then the population that recovers has the allele frequency reflecting the survivor pool and not the initial population

66
Q

The reality - Bottleneck leads to

A

the amplification of rare alleles that give carriers a selective advantage

67
Q

The reality - bottleneck and recovery will do what to the allele frequency in the pool

A

Change it

68
Q

Selection and genetic drift will do what do the allele frequency in the pool

A

Change it

69
Q

Assortative mating will do what do the allele frequency in the pool

A

NOT change it! It will just change the fraction of homozygous individuals

70
Q

The effects of selection - selection ___ the frequency of alleles that ___ fitness

A

Reduces the frequences of alleles that reduce fitness

71
Q

The effects of selection - Dominant mutant alleles

A

Disappear quickly if not constantly regenerated by new mutations
New mutations make up for the disappearance of old mutations due to fitness

72
Q

Positive selection - who has the advantage

A

Heterozygotes often have an advantage - wider spectrum of enzyme activity

73
Q

Positive selection - Some alleles provide advantage only in what state

A

Heterozygous

and will cause disease when homozygous

74
Q

Positive selection - it is hypothesized that what event selects positively for heterozygotes

A

Typhoid fever may select for CFTR mutations - people with mutation of CFTR have less severe typhoid fever
Malaria may select for B hemoglobin mutations

75
Q

Founder Effect - what was the in class example

A

Ellis van Crefeld Syndrome (EVS)
Many members of community are descendants of the founder - marriages became consanguineous - no influx of new alleles and so can’t avoid consanguinity

76
Q

Polymorphisms and disease - Polymorphisms may be at the root of many susceptibilities - what was example in class

A

Vit D receptor is a polymorphic gene

This polymorphism is correlated with increased risk of diseases like cancer and diabetes

Semester 5 FSNM Exam 9 (4 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions