Genetics

Question 1

Single gene determines phenotype regardless of other genes or environmental influences

Answer 1

Monogenic inheritance

Question 2

Configuration of alleles at a given locus

Answer 2

Allelic constitution

Question 3

Two defective alleles present

Answer 3

Heteroallelic

Question 4

Different alleles at same locus, or gene, give rise to same/similar disease

Answer 4

Allelic heterogeneity

Question 5

Cystic fibrosis and muscular dystrophy (duchenne’s, becker’s) exhibit

Answer 5

Allelic heterogeneity

Question 6

Genes at different loci (genes) cause same/similar disease

Answer 6

Locus heterogeneity

Question 7

Cells can’t convert phenylalanine to tyrosine

Answer 7

PKU

Question 8

Cofactor that serves as reducing agent in phenylalanine hydroxylase reaction

Answer 8

BH4

Question 9

PKU exhibits

Answer 9

Locus heterogeneity

Question 10

Gene with multiple alleles gives rise to same/similar disease

Answer 10

Allelic heterogeneity

Question 11

One of several genes give rise to same/similar disease

Answer 11

Locus heterogeneity

Question 12

Mendelian

Answer 12

Monogenic inheritance

Question 13

Disruption of mitochondrial energy production is

Answer 13

Pleiotropic

Question 14

Mixture of mitochondrial genome. Some wild type and some mutant

Answer 14

Heteroplasmy

Question 15

2 or more genes interact to give actual phenotype. No environmental effects

Answer 15

Polygenic inheritance

Question 16

All other genes that influence the action of the gene in question

Answer 16

Genetic background

Question 17

Sex influenced traits (autosomal defect), incomplete penetrance, and variable expressivity arise from

Answer 17

Gene-gene interactions

Question 18

Variant allele present in greater than one percent of the allelic population

Answer 18

Polymorphism

Question 19

Probability of manifesting a trait (phenotype) given the presence of a defective allele. Either or phenomenon. Target and modifier genes determine phenotypic outcome

Answer 19

Penetrance

Question 20

Incomplete penetrance found only in

Answer 20

Dominant modes of inheritance

Question 21

Looks like a combo of both recessive and dominant. Disease skips a generation

Answer 21

Incomplete penetrance pedigree

Question 22

Completely (100%) penetrant with variable age of onset

Answer 22

Huntington’s

Question 23

# cases w/ phenotype 
-------------------------
# cases w/ genotype

Answer 23

% penetrance

Question 24

Retinitis pigmentosa has true

Answer 24

Polygenic inheritance

Question 25

For polygenic modes (like incomplete penetrance), _____________ genes determine phenotypic outcome

Answer 25

2 or more

Question 26

Caused by genomic instability

Answer 26

Allelic heterogeneity

Question 27

2nd most common cause of intellectual disability and most common hereditary form of MR

Answer 27

Fragile X syndrome

Question 28

Secondary constriction on X Chr which is a site of frequent breakage. Site fails to condense during metaphase

Answer 28

Fragile X syndrome

Question 29

Males - moderate intellectual disability, large heads, large protruding ears, stubby hands, prominent jaw, delayed language development, inattention, and hyperactivity

Answer 29

Fragile X syndrome

Question 30

Carrier females are rarely physically dysmorphic, but they do have some learning disorders and they tend to be shy

Answer 30

Fragile X syndrome

Question 31

Fragile X is a ____ trait

Answer 31

Dominant (b/c carrier females have an affected phenotype)

Question 32

Phenotype variation in females with fragile X syndrome is due to

Answer 32

Unequal lionization

Question 33

Phenotypically normal man who passes the diseased allele on to his daughters and grandsons is called a

Answer 33

Nonpenetrant transmitting male

Question 34

Position in pedigree determines risk of developing syndrome

Answer 34

Sherman paradox