2.20 Usual and Unusual Patterns of Inheritance in Genetics Flashcards Preview

01 Cell > 2.20 Usual and Unusual Patterns of Inheritance in Genetics > Flashcards

Flashcards in 2.20 Usual and Unusual Patterns of Inheritance in Genetics Deck (68)
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

Genetics

2

About similarities and differences

Genetics

3

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

Genes

4

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

C. elegans
Chimpanzee
Mouse

5

Gene responsible for the gift of gab/language

FOXP2 gene at chromosome 2

6

22 chromosome pairs are ___ and ___

Autosome
Homologous

7

23rd pair contains ____

Sex chromosome

8

Carries genes responsible for many hereditary traits

X chromosome

9

Full set of chromosomes in the cell of a person

Karyotype

10

Genetic material

DNA

11

Size of human genome

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

12

Human Genome
Less than 2% code for ___

Proteins

13

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

Junk DNA

14

Human Genome
__ of bases are exactly the same in all people

99.9%

15

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

Normal protein vs. Low or nonfunctional protein

16

AAATTT >>> AATTTT
Cause no negative effect

Single nucleotide polymorphism

17

AAATTT>>>AACTTT
Can lead to disease or higher susceptibility to disease

Low or non-functioning protein

18

Marfan's syndrome
Sickle cell anemia
Cystic fibrosis

Single gene disorders

19

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

Complex gene disorders

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

Epigenetics

21

Epigenetic mechanisms are affected by factors such as

Development in utero
Environmental chemicals
Drugs/pharmaceuticals
Aging

22

View that genes cause traits and can no longer be altered

Genetic determinism

23

Your genes dictate who you are

Genetic determinism

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

Family History

25

When taking a family history

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

26

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

Proband

27

Individual presenting for genetic counseling
Not necessarily affected

Consultand

28

Graphic representation of a medical family history of disease using symbols

Pedigree

29

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

Pedigree

30

Confounding factors in recognizing patterns of inheritance

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

31

Tongue-rolling

Dominant

32

Cleft-chin

Dominant

33

Dimples

Dominant

34

Attached ear lobe

Recessive

35

Hitchhiker's thumb

Dominant

36

The genotype of an affected individual in autosomal dominant inheritance

AA
Aa

37

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

True

38

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

50%

39

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

False
Males and females are affected in equal proportion

40

Characteristics of autosomal dominant inheritance

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

41

Examples of autosomal dominant inheritance

Achondroplasia
Crouzon syndrome
Apert syndrome
Marfan syndrome
Ehlers-Danlos syndrome

42

Autosomal dominant inheritance usually involve ___

Structural proteins

43

The genotype of affected individual in autosomal recessive inheritance

aa

44

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

25%

45

True or false
Autosomal recessive inheritance skips generation

True

46

The genotype of carrier individual in autosomal recessive inheritance

Aa

47

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

False
Males and females are affected equally

48

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

50%
100%
25%; 50%

49

Characteristics of Autosomal Recessive Inheritance

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

50

Examples of genetic disorders with autosomal recessive inheritance

Harlequin baby
Mucopolysaccharidosis Type I Hurler
Maple Syrup Urine Disease
Galactosemia

51

Affected genotypes for X-linked recessive inheritance

XaY or XaXa

52

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

True

53

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

False
There is no father-to-son transmission

54

Characteristics of x-linked recessive inheritance

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

55

Examples of x-linked recessive inheritance

Duchenne Muscular Dystrophy
Mucopolysaccharidosis Type II Hunter

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

50%

57

Example of X-linked dominant inheritance

Rett syndrome

58

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

Multifactorial inheritance

59

Example of disorders associated with multifactorial inheritance

Oral Clefts
Neural tube defect
Pyloric stenosis

60

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

Mitochondrial inheritance

61

Mixture of mutated and non-mutated mitochondrial DNA

Heteroplasmy

62

Either all mutated or all non-mutated mitochondira

Homoplasmy

63

Explains the variable expression of mitochondrial DNA

Homoplasmy vs. heteroplasmy

64

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

Triple expansion disorders

65

Examples of triple expansion disorders

Myotonic dystrophy
Fragile X syndrome
Huntington's disease

66

Only one copy of the gene is expressed

Genomic imprinting

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

Epigenetic phenomenon

68

Examples of disorders associated with genomic impirnting

Prader-Willi Syndrom
Angelman syndrome