Genetics

Question 1

Penetrance

Answer 1

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

Question 2

Expressivity

Answer 2

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

Question 3

Genetic Herogeneity results from

Answer 3

Allelic heterogeneity and Locus Hertogeneiety

Question 4

Allelic Heterogeneity

Answer 4

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

Question 5

Locus Heterogeneity

Answer 5

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

Question 6

Compound Heterozygote

Answer 6

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

Question 7

CGH requires

Answer 7

Comparative Genome Hybridization

Reference DNA

Question 8

CGH detects

Answer 8

Trisomy, gross chromosome imblanace

Small deletions or duplications below the resolution of conventional cytogenetics

Question 9

FISH

Answer 9

detects DNA sequence without breaking up the cells

used for deletions greater than 100-500kb

Question 10

Souther Blot hybridization

Answer 10

uses digested cellular DNA with restriction enzymes

1-20kb

Question 11

Oligonucleotide hybridization (dot blot)

Answer 11

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

Question 12

Microarrays

Answer 12

Detect specific DNA sequences

single nucleotide to 500kb

Question 13

PCR

Answer 13

Detects size and sequence of DNA

Question 14

Direct Sequencing

Answer 14

detects the exact nucleotide sequence

Question 15

Epigenetics

Answer 15

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

Question 16

X inactivation

Answer 16

In females, extra X chromosome is turned off

N-1 rule

Question 17

DNA methylation

Answer 17

Inhibits DNA from being read by winding DNA tightly

Question 18

Histone Acetylation

Answer 18

Promotes DNA being read by unwinding

Question 19

Genomic Imprinting

Answer 19

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

Question 20

Prader Willi

Answer 20

lack of paternal 15q11-q13

Question 21

Angelman Syndrome

Answer 21

lack of maternal 15q11-q13

Can also be a lack of gene UBE3A

Question 22

Rules for HW

Answer 22

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

Question 23

Factors that Ruin HW

Answer 23

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.

Question 24

Founder Affect

Answer 24

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

Question 25

Heterozygote Advantage

Answer 25

Alleles where heterozygotes may show increased fitness.

Question 26

Relative Risk

Answer 26

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

Question 27

Concordance

Answer 27

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

Question 28

Heritability

Answer 28

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

Question 29

Haplotype

Answer 29

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

Question 30

Complete disequilibrium

Answer 30

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

Question 31

Complete equilibrium

Answer 31

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

Question 32

tagSNP

Answer 32

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

Question 33

Phenylalanine to tyrosine is done by

Answer 33

``` phenylalanine hydroxylase (PAH) A deficiency leads to PKU ```

Question 34

Congenital

Answer 34

Present at birth

Question 35

Major Anomaly

Answer 35

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

Question 36

Minor Anomaly

Answer 36

Generally does not require intervention or easily corrected

Question 37

Types of morphogenic abnormalities

Answer 37

Malformation Deformation Disruption Dysplasia

Question 38

Malformation

Answer 38

congential | usually occurs by 8-10 weeks gestation

Question 39

Malformation Syndrome

Answer 39

pattern of features often involving multiple organ systems | Unifying underlying cause

Question 40

Association

Answer 40

Non random occurence of anomalies where the etiology is unknown

Question 41

Deformation

Answer 41

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

Question 42

Disruption

Answer 42

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

Question 43

Dysplasia

Answer 43

abnormal cellular organization within a tissue resulting in structural changes

Question 44

Marfan Syndrome

Answer 44

Autosomal Dominant

Question 45

Duchenne Muscular Dystophy

Answer 45

X linked Recessive

Question 46

Rett Syndrome

Answer 46

X linked dominant

Question 47

Cystic Fibrosis

Answer 47

Autosomal Recessive

Question 48

Disease Incidence

Answer 48

q^2

Question 49

Myotonic Dystrophy

Answer 49

Unstable repeat expansion