Genetics Flashcards

1
Q

Penetrance

A

The proportion of people with the relevant genotype who show the character
i.e. is the phenotype expressed or not (binary)

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2
Q

Expressivity

A

Affected people show only some of the feature, or may show a certain feature to different degrees
i.e. sliding scale

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3
Q

Genetic Herogeneity results from

A

Allelic heterogeneity and Locus Hertogeneiety

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4
Q

Allelic Heterogeneity

A

situation where a clinical condition can be caused by any of several different mutations within a SINGULAR gene
i.e CF

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5
Q

Locus Heterogeneity

A

situation where a clinical condition can be caused by any of several mutations on multiple genes

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6
Q

Compound Heterozygote

A

A person with a recessive condition who has 2 different mutant versions of a gene

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7
Q

CGH requires

A

Comparative Genome Hybridization

Reference DNA

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8
Q

CGH detects

A

Trisomy, gross chromosome imblanace

Small deletions or duplications below the resolution of conventional cytogenetics

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9
Q

FISH

A

detects DNA sequence without breaking up the cells

used for deletions greater than 100-500kb

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10
Q

Souther Blot hybridization

A

uses digested cellular DNA with restriction enzymes

1-20kb

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11
Q

Oligonucleotide hybridization (dot blot)

A

Detects single base changes
Need to know SNP you are looking for
(single nucleotide)

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12
Q

Microarrays

A

Detect specific DNA sequences

single nucleotide to 500kb

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13
Q

PCR

A

Detects size and sequence of DNA

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14
Q

Direct Sequencing

A

detects the exact nucleotide sequence

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15
Q

Epigenetics

A

Refers to how DNA is packaged that in chromatin rather than of changes in DNA sequence

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16
Q

X inactivation

A

In females, extra X chromosome is turned off

N-1 rule

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17
Q

DNA methylation

A

Inhibits DNA from being read by winding DNA tightly

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18
Q

Histone Acetylation

A

Promotes DNA being read by unwinding

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19
Q

Genomic Imprinting

A

Only one allele, either paternal or maternal is expressed in the relevant tissue

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20
Q

Prader Willi

A

lack of paternal 15q11-q13

21
Q

Angelman Syndrome

A

lack of maternal 15q11-q13

Can also be a lack of gene UBE3A

22
Q

Rules for HW

A
Pop is large
Allele frequency is constant over time
No rate of new mutations
No immigration 
Random mating
23
Q

Factors that Ruin HW

A

Stratification: population contain subgroups
Assortative mating: choosing a mate who is genetically similar to ones self.
Consanguinity and inbreeding: problem when carriers with AR disorders mate
Migration and Gene Flow: migration can change allele frequency.

24
Q

Founder Affect

A

Small group of people who start a population have higher likely hood of certain traits

25
Q

Heterozygote Advantage

A

Alleles where heterozygotes may show increased fitness.

26
Q

Relative Risk

A

prevalence of disease in relatives / prevalence of disease in general pop

27
Q

Concordance

A

When related individuals have the same disease (good for twin studies)

28
Q

Heritability

A

V(DZ)-V(Mz) / V(Dz)

29
Q

Haplotype

A

A set of closely linked alleles on a single chromosome that is normally inherited as a block

30
Q

Complete disequilibrium

A

Two alleles are closely linked together and do no separate over many generations

31
Q

Complete equilibrium

A

Two alleles are far apart and thus have a great high recombination frequency and will separate over few generations.

32
Q

tagSNP

A

A collection of SNPs within a haplotype block that can be used to identify the haplotype block.

33
Q

Phenylalanine to tyrosine is done by

A
phenylalanine hydroxylase (PAH)
A deficiency leads to PKU
34
Q

Congenital

A

Present at birth

35
Q

Major Anomaly

A

severe enough to require intervention
Possibly life threatening
May result in life long morbidity / disability

36
Q

Minor Anomaly

A

Generally does not require intervention or easily corrected

37
Q

Types of morphogenic abnormalities

A

Malformation
Deformation
Disruption
Dysplasia

38
Q

Malformation

A

congential

usually occurs by 8-10 weeks gestation

39
Q

Malformation Syndrome

A

pattern of features often involving multiple organ systems

Unifying underlying cause

40
Q

Association

A

Non random occurence of anomalies where the etiology is unknown

41
Q

Deformation

A

Compression or mechanical distortion of an already normally formed body part
Usually occurs after 8-10 weeks

42
Q

Disruption

A

destruction of a tissue that was previously normal or in the process of forming normally

43
Q

Dysplasia

A

abnormal cellular organization within a tissue resulting in structural changes

44
Q

Marfan Syndrome

A

Autosomal Dominant

45
Q

Duchenne Muscular Dystophy

A

X linked Recessive

46
Q

Rett Syndrome

A

X linked dominant

47
Q

Cystic Fibrosis

A

Autosomal Recessive

48
Q

Disease Incidence

A

q^2

49
Q

Myotonic Dystrophy

A

Unstable repeat expansion