Principles of Genetic Inheritance

Question 1

mtDNA problems

Answer 1

no repair mechanisms, HELLA mutations

Question 2

mt Inheritance Pedigree

Answer 2

all of mother’s offspring are affected

Question 3

Leber’s Hereditary Optic Neuropathy (LHON)

Answer 3

degeneration of retinal ganglion cells

caused by mtDNA point mutation affecting NADH dehydrogenase

Question 4

Myoclonic Epilepsy and Ragged Red Fibers (MERRF)

Answer 4

caused by mutation in the gene encoding for tRNA for lysine, which messes up the synthesis of cyt-C oxidase

(muscles and nerves)

Question 5

Mitochondrial Encephalomyopathy, Lactic Acidosis, and Stroke-like Episodes (MELAS)

Answer 5

-most common maternally-inherited mt disease-

caused by single point mutation preventing pyruvate use, making body use lactic acid

Question 6

What is a euploid?

Answer 6

cells with a normal number of chromosomes

Question 7

Polyploidy

Answer 7

cells contain a complete set of extra chromosomes in cells (plants)

Question 8

Aneuploidy

Answer 8

cells contain a missing or additional individual chromosome(s)
–monosomy, trisomy

Question 9

Genomic Imprinting

Answer 9

gene silencing through methylation of 5’ region of gene

Question 10

Uniparental Disomy

Answer 10

two chromosomes are inherited from the same parent

Question 11

Turner Syndrome

Answer 11

Karyotype: 45, XO (missing an X)

short, do not go through puberty, infertile, cv defects

Question 12

Angelman Syndrome

Answer 12

maternal deletion of chromosome 15, severe intellectual disability

Question 13

Prader-Willi Syndrome

Answer 13

paternal deletion of chromosome 15, short, obese, uncontrolled eating, intellectual disability

Question 14

Angelman Syndrome

Answer 14

maternal deletion of chromosome 15, severe intellectual disability

Question 15

Klinefelter Syndrome

Answer 15

Karyotype: 47, CXXY

Question 16

Trisomy 21

Answer 16

Down Syndrome
Karyotype: 47, XX +21
most common

Question 17

Trisomy 18

Answer 17

Edwards Syndrome
Karyotype: 47, XX +18
most die in utero, and few survive beyond 1 yr.
microencephaly, cleft lip/palate, o

Question 18

Trisomy 13

Answer 18

Patau Syndrome
Karyotype: 47, XX +13

Severe developmental abnormalities
In utero death, die shortly after birth
heart abnormalities, kidney malformations, CNS dysfunction

Question 19

Trisomy 13

Answer 19

Patau Syndrome
Karyotype: 47, XX +13

Severe developmental abnormalities
In utero death, die shortly after birth
heart abnormalities, kidney malformations, CNS dysfunction

Question 20

Reduced/Incomplete Penetrance

Answer 20

frequency a gene is phenotypically shown (100% would mean that all people with genetic defect show it)

Question 21

Retinoblastoma

Answer 21

Autosomal dominant

phenotype occurs 90% of individuals, meaning 90% penetrance

Question 22

Locus Heterogenetiy

Answer 22

Single disorder, trait, or pattern of traits caused by mutation in genes at different chromosomal loci
-aka only one mutant locus is needed for the effect to be seen phenotypically

Question 23

Independence

Answer 23

occurrence of one does not affect the probability of occurrence of the other

Question 24

Hardy-Weinberg Principle

Answer 24

relationship between gene frequency and genotype frequency

useful for estimating gene frequency from Disease Prevalence Data

Question 25

Hardy-Weinberg Equation

Answer 25

p^2 + 2pq + q^2 = 1