Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

Foundation of Medical Genetics > Midterm > Flashcards

Midterm Flashcards

1
Q

Single-gene disease inheritance depends on

A
  1. where the gene is located (autosome v. sex chromosomes)
  2. how the phenotype is express (recessive v. dominant)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Can be observed in multiple generations within a pedigree

A

Autosomal Dominant

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

Law of Addition

A

add the probabilities of two mutually exclusive events to get probability of either event occurring
“or”

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

Law of Multiplication

A

multiply probabilities of independent events to get the probability of. more than one occurring
“and”

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

Penetrance

A

probability that a mutant allele will have any phenotypic expression

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

incomplete penetrance

A

when individuals with a disease causing genotype completely fail to express the phenotype

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

expressivity

A

degree of severity of a phenotype- the degree to which the phenotype is expressed

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

variable expressivity

A

when severity of a disease between individuals with the same genotype varies

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

Carrier frequency

A

the proportion of individuals in a population who are carriers for a genetic condition

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

Example of X-linked Recessive

A

red-green color blindness

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

Compound heterozygous

A

The presence of two different mutated alleles at a particular gene locus

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

gene

A

gene is a basic unit of heredity and the molecular gene is a sequence of nucleotides in DNA that is transcribed to produce a functional RNA

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

allele

A

one specific variant for a given polymorphism

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

Skewed X-inactivation

A

due to random chance or reduced survival of cells expressing a particular X chromosome

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

Pseudoautosomal inheritance

A

Genes on the Y-chromosome are sometimes passed to daughters, and genes on the X-chromosome are sometimes passed from fathers to their sons. This is possible because the X- and Y-chromosomes share regions of sequence identity, and these regions undergo recombination during male meiosis.

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

Example of X-linked dominant w/ Male Lethality

A

Incontinetia pigmenti
focal dermal hyperplasia

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

Possible living offspring of an affected female with x-linked dominant w/ male lethality

A

affected female, unaffected female, unaffected male

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

Examples of X-linked dominant with male sparing

A

craniofacial dysplasia
epilepsy w/ intellectual disability

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

Effects of x linked dominant w/ male sparing on females v. males

A

heterozygous females are affected, males are not or minimally affected, unaffected male leads to affected female transmission

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

Mosaicism

A

Presence of at least two different cell lineages that contain genetic differences but are derived from the same zygote

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

confined placental mosaicism

A

cells in the placenta differ from cells in the embryo

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

somatic mosaicism

A

differing cell populations within somatic tissue, but gametes identical

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

germline mosaicism

A

differing cells only in gametes
example: mutation in FBN1 (Marfan)

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

Nuerofibromstosis Type 1 (NF1)

A

AD condition caused by mutations in NF1 gene (tumor suppressor) 50/50 de nov/inherited

phenotypes: Cafe au lait spots, linch nodules, nerve tumors, axillary freckling, optic glioma, plexiform neurofibromas

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Genomic Imprinting
A process of silencing genes through DNA methylation. The repressed allele is methylated, while the active allele is unmethylated. Which copy is active depends on the parent of origin: some genes are normally active only when they are inherited from a person’s father; others are active only when inherited from a person’s mother Examples include Prader-Willi and Angelman syndromes (the first examples of genomic imprinting in humans).
26
Prader-Willi Syndrome
Parent of origin effects- loss of maternally expressed genes incidence 1/20000 characterized by severe hypotonia and feeding difficulties in the neonatal period, obesity, developmental delay
27
Angelman Syndrome
parent of origin effects- loss of paternally expressed genes incidence 1/15000 characterized by seizure disorder, ataxic gait, happy appearance w/ inappropriate laughter
28
unstable repeat expansions
dynamic mutations that change from generation to generation larger repeat= increased severity i.e. huntingtons, fragile X, myotonic dystrophy
29
Huntington Disease
progressive neurologic condition of motor, cognitive and psychiatric impairment caused by CAG repeats normal <26 intermediate 27-35 HD causing- >36
30
anticipation
increasing disease severity or decreasing age of onset is observed in successive generations i.e. HD, myotonic dystrophy
31
mitochondria inheritance have three unique features
maternal inheritance, replicative segregation, homoplasmy/ heteroplasmy
32
heteroplasmy
differences in the mtDNA between the different mitochondria within a cell
33
allelic heterogeneity
different mutation in a gene may produce the same phenotype i.e. >1000 mutations cause CF
34
locus hetergeneity
mutations in different genes may cause the same phenotype
35
clinical or phenotypic heterogeneity
different mutations in a gene may result in different phenotypes
36
euploidy
abnormal copies in all chromosomes
37
aneuploidy
abnormal copies iof a single chromosome
38
uniparental disomy
disomic state where both chromosomes are inherited from the same parent
39
isodisomy
chromsomes inherited from sister chromatids
40
heterodisomy
inheritance of both homologs from one parent
41
marker chromosomes
is a rearranged small chromosome whose genetic origin is unknown based on its G-banded chromosome morphology can contain material from one or both chromosome arms called ring chromosomes when they lack telomeres
42
isochromosomes
arm of one chromosome is duplicated creates a mirrored chromosome, with both arms containing duplicated genetic material results in trisomy of the duplicated arm and monosomy of the non duplicated arm
43
reciprocal translocation
recombination between nonhomologous chromosomes can be balanced or unbalanced balanced typically have no effect high risk for unbalanced gametes
44
robertsonian translocations
fusion of two eccentric chromosomes near the centromere loss of short arms of the fused chromosomes
45
causes of Down syndrome
95% trisomy 21 4% robertsonian translocation
46
causes of turner syndrome
50% 45,X 25% structural abnormality of X (isochromsome) 25% 45, X mosaicism
47
causes of turner syndrome
50% 45,X 25% structural abnormality of X (isochromsome) 25% 45, X mosaicism
48
how can we identify chromosomal alterations
karyotype FISH Microarray
49
karyotype
used to identify microscopic changes in chromosomes number or configuration
50
FISH
can identify submicroscopic changes in chromosomes structure and rearrangements
51
microarray
identify submicroscopic changes in copy number
52
population
group of interbreeding individuals of the same species sharing a common geographic area
53
Causes of allele frequency change
bottleneck events, mutations, natural selection, migration, nonrandom mating,
54
Assumptions of Hardy Weinberg
random mating, no natural selection,, large population size, no migration or gene flow between populations
55
How similar are humans to each other...
99.9%
56
linkage disequilibrium
the nonrandom association of alleles at different loci (on the same chromosome)
57
haplotypes
a set of DNA variants along a single chromosome that tend to be inherited together.
58
who discovered structure of DNA
Maurice Wilkins + Rosalind Franklin James Watson and Francis Crick
59
How many genes in human genome?
25,000
60
How many basepairs per haploid in the human genome?
3.2 billion
61
How many basepairs per haploid in the human genome?
3.2 billion
62
genome
the entire genetic make up of an organism
63
polymorphism
any DNA sequence variation
64
genotype
the combined alleles at a specific locus
65
haplotype
alleles from different loci occur on the same chromosome
66
phenotype
the observable or measurable trait
67
Single nucleotide polymorphisms
single base changes
68
synonymous mutation
change in one DNA base pair without changing amino acid sequence AGG->AGA
69
missense mutation
change in one DNA base pair that results in one amino acid change CCT->CTT
70
nonsense mutation
change in one DNA base pair that results in STOP codon and shortened protein CAG->TAG
71
frameshift mutation
add or remove a piece of DNA base pairs, not multiple of 3 base pairs
72
repeat expansion
repeat a piece of DNA base pair(s) a number of times
73
What can we tell from Hardy Weinberg Equilibrium
whether or not a species is evolving, allele frequencies are changing
74
Central Dogma
DNA to RNA transcript to mature mRNA to protein
75
mRNA 5' capping
stabilizes transcript
76
Promoters
upstream (5') of the transcription start site
77
Eukaryotic Transcription
DNA is in a loose configuration general transcription factors must bind to promoter sequence prior to RNA polymerase Specific transcription factors bind to enhancer sequences to regulate transcription
78
RNA processing
must happened for RNA to be functional 1. 5' capping 2. exon splicing 3. poly-A addition
79
mRNA splicing
removes introns of gene, unique to eukaryotes, allows for mutations to occur with less chance of a detrimental effect, allows for more complex proteins to be created
80
mRNA Polyadenylation
sequence indicates cleavage of the mRNA about 20 nucleotides downstream
81
P site in Translation
Peptidyl site, binds to the tRNA holding the growing polypeptide chain of amino acids
82
A site in Translation
acceptor site; binds to the aminoacyl tRNA, which holds the new amino acid to be added to the polypeptide chain
83
E site in Translation
exit site, serves as a threshold, the final transitory step before a tRNA now bereft of its amino acid is let go by the ribosome
84
What two components are needed for effective gene expression regulation
1. cis-acting elements (DNA consensus sequences) 2. Tran-acting factors (Gene regulatory proteins)
85
Histone acetylation
leads to gene activation
86
positional cloning
identifies a disease gene based solely on its position in the genome, independent of its function combines linkage analysis with physical mapping can identify a previously unknown gene or regulatory sequence
87
Cystic Fibrosis
AR, Gene CFTR; one gene many mutations
88
Reduced genetic variation is observed
with distance from Africa
89
Which SNPs are functionally important?
no clue, were not sure which SNPs have functional relevance
90
DNA Structure
phosphodiester backbone, deoxyribose sugar, nitrogenous bases

Foundation of Medical Genetics (1 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions