Inheritance

Question 1

What is the normal male genotype?

Answer 1

XY.

Question 2

What is the normal female genotype?

Answer 2

XX.

Question 3

What is sickle cell disorder caused by?

Answer 3

Abnormal haemoglobin gene.

Question 4

What is cystic fibrosis caused by?

Answer 4

Single gene.

Question 5

How many people are affected by CF?

Answer 5

1/25 carrier

1/2500 affected

Question 6

What chance does each child have of inheriting trait in autosomal dominant inheritance?

Answer 6

50%

Question 7

Does autosomal dominant inheritance skip generations?

Answer 7

No.

Question 8

What are examples of autosomal dominant inheritance?

Answer 8

Achondroplasia

Huntington’s Disease

Question 9

What is achondroplasia?

Answer 9

Autosomal dominant- dwarfism.

Question 10

What is Huntington’s disease?

Answer 10

Autosomal dominant- neurodegenerative.

Question 11

What is Duchennes Muscular Dystrophy caused by?

Answer 11

X-linked.

Question 12

Who is affected in X-linked inheritance?

Answer 12

Males.

Question 13

Can X-linked inheritance skip generations?

Answer 13

Yes.

Question 14

Who can transmit in X-linked inheritance?

Answer 14

Unaffected women and affected men.

Question 15

Is male-male transmission present in X-linked inheritance?

Answer 15

No.

Question 16

What are the 3 types of chromosome abnormality?

Answer 16

Numerical
Structural
Mutational

Question 17

What are numerical abnormalities based on?

Answer 17

Trisomy

Monosomy

Question 18

What is non-dysjunction?

Answer 18

The failure of homologous chromosomes to separate properly during cell division.

Question 19

What are autosomal aneuploidy syndromes?

Answer 19

The presence of an abnormal number of chromosomes in a non-sex chromosome.

Question 20

What are 3 examples of autosomal aneuploidy syndromes?

Answer 20

Down syndrome
Patau syndrome
Edwards syndrome

Question 21

What is a Trisomy 21 aneuploidy syndrome?

Answer 21

Downs syndrome.

Question 22

What characterises Down syndrome?

Answer 22

Facial dysmorphologies, low IQ, lower life expectancy.

Question 23

What is a Trisomy 13 aneuploidy syndrome?

Answer 23

Patau syndrome.

Question 24

What characterises Patau syndrome?

Answer 24

Mental retardation / facial dysmorphia.

Question 25

What is a Trisomy 18 aneuploidy syndrome?

Answer 25

Edwards syndrome.

Question 26

What characterises Edwards syndrome?

Answer 26

Severe developmental problems.

Question 27

What are sex chromosome aneuploidy syndromes?

Answer 27

Syndromes of abnormal chromosome number in sex chromosomes.

Question 28

Give 2 examples of sex chromosome aneuploidy syndromes.

Answer 28

Turner | Klinefelter

Question 29

What happens in Turner syndrome?

Answer 29

X chromosome loss- wide nipples, short stature, infertile, neck webbing.

Question 30

What happens in Klinefelter syndrome?

Answer 30

Extra XXY chromosome- tall stature, long limbs, male but infertile, small testes, mild learning difficulties.

Question 31

What can mutational abnormalities be?

Answer 31

Balanced or unbalanced.

Question 32

What are the 4 types of mutational abnormality?

Answer 32

Silent Missense Nonsense Frameshift

Question 33

What is a silent mutation?

Answer 33

Synonymous with normal function.

Question 34

What is a missense mutation?

Answer 34

Doesn't fit.

Question 35

What is a nonsense mutation?

Answer 35

Stop codon- prevents development.

Question 36

What is a frameshift mutation?

Answer 36

Deletion / insertion.

Question 37

What are the differences between the general genome and the mitochondrial genome?

Answer 37

General has more genes, less coding though. | Nuclear deals with mendelian inheritance; mitochondrial deals with maternal inheritance.

Question 38

What shape is mitochondrial DNA?

Answer 38

Loop.

Question 39

How many copies of genes are in nuclear genome?

Answer 39

2

Question 40

How many copies are in mitochondrial genome?

Answer 40

Thousands- polyploidy present.

Question 41

What is homoplasmy / heteroplasmy?

Answer 41

The fact that mitochondrial DNA can be from same or different populations.

Question 42

Why is the mitochondrial genome a mutation hotspot?

Answer 42

Lack efficient DNA repair system | Lack protective proteins.

Question 43

What are examples of mitochondrial disease?

Answer 43

LHON | MELAS

Question 44

What is genomic imprinting?

Answer 44

When genes are expressed from only one chromosome.

Question 45

What happens with 2 maternal genomes?

Answer 45

Normal embryo | Abnormal membrane / placenta

Question 46

What happens with 2 paternal genomes?

Answer 46

Abnormal embryo | Normal membrane / placenta

Question 47

What are some human models of genetic imprinting?

Answer 47

Angelmans syndrome | Prader-Willi

Question 48

Is Prader-Willi or Angelmans maternal?

Answer 48

Prader-Willi.

Question 49

What does Angelmans syndrome lack?

Answer 49

Lacks maternal chromosome.

Question 50

What does Prader-Willi syndrome lack?

Answer 50

Lacks paternal chromosome.

Question 51

What does methylation do?

Answer 51

Marks the chromosome- stops transcription.

Question 52

How are famine and schizophrenia linked?

Answer 52

Famine exposure provides increased link to schizophrenia.

Question 53

What is the polygenic risk score?

Answer 53

Risk factor scale for polygenic risk.