2.20 Usual and Unusual Patterns of Inheritance in Genetics

Question 1

Science that deals with heredity and variation in organisms, including the genetic features and constitution of a single organism, species or group and with the mechanisms by which they are affected

Answer 1

Genetics

Question 2

About similarities and differences

Answer 2

Genetics

Question 3

Biological maps that tell us who we are, where we came from and how we are related to other creatures

Answer 3

Genes

Question 4

Human genome is 75% homologous to ___; 98.7% homologous to ___; and 99% homologous to ___.

Answer 4

C. elegans
Chimpanzee
Mouse

Question 5

Gene responsible for the gift of gab/language

Answer 5

FOXP2 gene at chromosome 2

Question 6

22 chromosome pairs are ___ and ___

Answer 6

Autosome

Homologous

Question 7

23rd pair contains ____

Answer 7

Sex chromosome

Question 8

Carries genes responsible for many hereditary traits

Answer 8

X chromosome

Question 9

Full set of chromosomes in the cell of a person

Answer 9

Karyotype

Question 10

Genetic material

Answer 10

DNA

Question 11

Size of human genome

Answer 11

3 B base pairs making up 22-25K genes varying in length

Question 12

Human Genome

Less than 2% code for ___

Answer 12

Proteins

Question 13

Human Genome

90% are sometimes called ___, important in regulation of gene expression, introns

Answer 13

Junk DNA

Question 14

Human Genome

__ of bases are exactly the same in all people

Answer 14

99.9%

Question 15

Variations or mutations in genes may have negative effects and lead to disease or increase susceptibility to disease

Answer 15

Normal protein vs. Low or nonfunctional protein

Question 16

AAATTT&raquo_space;> AATTTT

Cause no negative effect

Answer 16

Single nucleotide polymorphism

Question 17

AAATTT»>AACTTT

Can lead to disease or higher susceptibility to disease

Answer 17

Low or non-functioning protein

Question 18

Marfan’s syndrome
Sickle cell anemia
Cystic fibrosis

Answer 18

Single gene disorders

Question 19

Diabetes, Hypertension
Variations in the gene, which lead to disease or increase susceptibility
Extent of interactions of various risk factors remains unknown

Answer 19

Complex gene disorders

Question 20

Study of the set of the chemical reactions and the factors that triggers the activation/deactivation of parts of the genome at strategic times and locations

Answer 20

Epigenetics

Question 21

Epigenetic mechanisms are affected by factors such as

Answer 21

Development in utero
Environmental chemicals
Drugs/pharmaceuticals
Aging

Question 22

View that genes cause traits and can no longer be altered

Answer 22

Genetic determinism

Question 23

Your genes dictate who you are

Answer 23

Genetic determinism

Question 24

Major activity and key factor in clinical genetics
Aid in reaching a correct diagnosis
One of the most useful and accessible tools available to physicians caring for patients with genetic diseases

Answer 24

Family History

Question 25

When taking a family history

Answer 25

Make it relevant to the present illness Ask about early onset preventable diseases Ask about first-degree relatives Ask about informative relatives (Proband and consultand) Record racial and ethnic background Inquire about consanguinity Keep it up to date

Question 26

First affected individuals in a family who brings genetic disorder to the attention of the medical community

Answer 26

Proband

Question 27

Individual presenting for genetic counseling | Not necessarily affected

Answer 27

Consultand

Question 28

Graphic representation of a medical family history of disease using symbols

Answer 28

Pedigree

Question 29

Provides both critical medical data and biological relationship information at a glance

Answer 29

Pedigree

Question 30

Confounding factors in recognizing patterns of inheritance

Answer 30

``` Variable expressivity Clinical or genetic heterogeneity Sex-influenced or sex-limited gene expression Assortative mating Small paternity size ```

Question 31

Tongue-rolling

Answer 31

Dominant

Question 32

Cleft-chin

Answer 32

Dominant

Question 33

Dimples

Answer 33

Dominant

Question 34

Attached ear lobe

Answer 34

Recessive

Question 35

Hitchhiker's thumb

Answer 35

Dominant

Question 36

The genotype of an affected individual in autosomal dominant inheritance

Answer 36

AA | Aa

Question 37

True or false | Male-to-male transmission occurs in autosomal dominant inheritance

Answer 37

True

Question 38

Each offspring has __ chance of being affected in autosomal dominant inheritance

Answer 38

50%

Question 39

True or false | Only males are affected in autosomal dominant inheritance.

Answer 39

False | Males and females are affected in equal proportion

Question 40

Characteristics of autosomal dominant inheritance

Answer 40

Affected genotype: AA or Aa Offspring has 50% chance of being affected Males and females affected in equal proportion Male-to-male transmission occurs

Question 41

Examples of autosomal dominant inheritance

Answer 41

``` Achondroplasia Crouzon syndrome Apert syndrome Marfan syndrome Ehlers-Danlos syndrome ```

Question 42

Autosomal dominant inheritance usually involve ___

Answer 42

Structural proteins

Question 43

The genotype of affected individual in autosomal recessive inheritance

Answer 43

aa

Question 44

In autosomal recessive inheritance, each offspring has __ chance of getting affected when both parents are carriers of a single copy of the gene

Answer 44

25%

Question 45

True or false | Autosomal recessive inheritance skips generation

Answer 45

True

Question 46

The genotype of carrier individual in autosomal recessive inheritance

Answer 46

Aa

Question 47

True or false | In autosomal recessive inheritance, only female is affected

Answer 47

False | Males and females are affected equally

Question 48

Autosomal recessive: One affected + one carrier = __ chance of being affected One affected + one not affected = __ chance of carrier Both are carriers = ___ affected, ___ carrier

Answer 48

50% 100% 25%; 50%

Question 49

Characteristics of Autosomal Recessive Inheritance

Answer 49

Affected gene: aa Must ask about consanguinity Affect males and females equally Skip generations

Question 50

Examples of genetic disorders with autosomal recessive inheritance

Answer 50

Harlequin baby Mucopolysaccharidosis Type I Hurler Maple Syrup Urine Disease Galactosemia

Question 51

Affected genotypes for X-linked recessive inheritance

Answer 51

XaY or XaXa

Question 52

True or false | In X-linked recessive inheritance, all daughters of affected males are carriers

Answer 52

True

Question 53

True or false | In X-linked recessive inheritance, there is no mother-to-daughter transmission

Answer 53

False | There is no father-to-son transmission

Question 54

Characteristics of x-linked recessive inheritance

Answer 54

Incidence higher in males Daughters of affected males are carriers (obligate carriers) No-father-to-son transmission

Question 55

Examples of x-linked recessive inheritance

Answer 55

Duchenne Muscular Dystrophy | Mucopolysaccharidosis Type II Hunter

Question 56

In x-linked dominant inheritance, a male or female child of an affected mother has a __ chance of inheriting the mutation and thus being affected with the disorder

Answer 56

50%

Question 57

Example of X-linked dominant inheritance

Answer 57

Rett syndrome

Question 58

Participation of environmental factors, not just genetic | Only those who reach threshold make up the affected population

Answer 58

Multifactorial inheritance

Question 59

Example of disorders associated with multifactorial inheritance

Answer 59

Oral Clefts Neural tube defect Pyloric stenosis

Question 60

Mother-related disease | Affected mom: all offspring will inherit the disease

Answer 60

Mitochondrial inheritance

Question 61

Mixture of mutated and non-mutated mitochondrial DNA

Answer 61

Heteroplasmy

Question 62

Either all mutated or all non-mutated mitochondira

Answer 62

Homoplasmy

Question 63

Explains the variable expression of mitochondrial DNA

Answer 63

Homoplasmy vs. heteroplasmy

Question 64

An expansion of a segment of DNA that contains a repeat of 3 nucleotides

Answer 64

Triple expansion disorders

Question 65

Examples of triple expansion disorders

Answer 65

Myotonic dystrophy Fragile X syndrome Huntington's disease

Question 66

Only one copy of the gene is expressed

Answer 66

Genomic imprinting

Question 67

Expression of the gene is variable depending on which parent the gene came from The active gene is preferentially always from one parent over the other

Answer 67

Epigenetic phenomenon

Question 68

Examples of disorders associated with genomic impirnting

Answer 68

Prader-Willi Syndrom | Angelman syndrome