MIDTERM LEC 1: MENDELIAN GENETICS Flashcards

1
Q

___________ - inheritance of a trait or characteristic that is controlled by a SINGLE GENE aka_____________

A

SINGLE-GENE INHERITANCE; MENDELIAN INHERITANCE

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2
Q

SINGLE-GENE TRAITS is also known as

A

MONOFACTORIAL TRAITS or MENDELIAN

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3
Q

CHARACTERISTICS OF SINGLE-GENE TRAITS

A
  1. Relationship with the affected relative
  2. Tests can sometimes predict the risk of developing symptomes
  3. More common in some populations than others
  4. It may be fixable
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4
Q

example of single-gene traits

A

widow’s peak, dimple, earlobes, albinism

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5
Q

Definition of terms
- alternative form of gene

A

ALLELE

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6
Q

Definition of terms
- allele that masks another, has an effect when present in just 1 copy (CAPITAL LETTER)

A

DOMINANT ALLELE

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7
Q

Definition of terms
- masked, must be present on both chromosomes of a pair to be expressed (small letter)

A

RECESSIVE ALLELE

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8
Q

Definition of terms
- 2 identical alleles (true - breeding)

A

HOMOZYGOUS

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9
Q

Definition of terms
- 2 different alleles (non-true breeding/hybrid)

A

HETEROZYGOUS

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10
Q

Definition of terms
- underlying instructions (alleles present)

A

GENOTYPE

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11
Q

Definition of terms
- visible trait, outward expression of an allele combination

A

PHENOTYPE

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12
Q

Definition of terms (what type of trait)
- 1 trait that masks another

A

DOMINANT TRAIT

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13
Q

Definition of terms (dominant or recessive trait)
- masked trait

A

RECESSIVE TRAIT

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14
Q

An organism’s appearance does not always reveal it’s alleles

TRUE or FALSE?

A

TRUE

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15
Q

Definition of terms
- phenotype, most common expression of a particular allele combination in a population

Wild or mutant type

A

WILD TYPE

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16
Q

Definition of terms
- phenotype, variant of a gene’s expression that arises when the gene undergoes CHANGE

A

MUTANT TYPE

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17
Q

Example of mutant type in Humans

A

Albino

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18
Q

Example of wild type in Humans

A

Caucasoid
Mongoloid
Negroid

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19
Q

MENDELS EXPERIMENT
In ________, Mendel crossed and cataloged traits in 24,034 plants, through several generations. He term units of heredity as “ELEMENTEN”.

A. 1857-1863
B. 1866
C. 1901

A

1857-1863

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20
Q

Mendel published “EXPERIMENT ON PLANT HYBRIDIZATION on” _______

A. 1857-1863
B. 1866
C. 1901

A

1866

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21
Q

HUGO DE VRIES (Holland), CARL CORRENS (Germany , and ERICH VON TSCHERMAK (Austria) used Mendel’s theory making him know into the field

A. 1857-1863
B. 1866
C. 1901

A

1901

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22
Q

Mendel term the unit of heredity as

A

ELEMENTEN

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23
Q

The term ELEMENTEN was renamed by ________ as “genes” (Greek for “give birth to”)

A

WILLIAM BATESON (1909)

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24
Q

Genes is Greek for

A

Give birth to

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25
Q

Why did Gregor Johann Mendel use pea plants in his experiment?

A
  • EASY TO GROW
  • DEVELOP QUICKLY
  • HAVE MANY TRAITS THAT TAKE ONE OF TWO EASILY DISTINGUISHABLE FORMS
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26
Q

In analyzing genetic crosses _________ is the first generation

A

Parental Generation or P1

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27
Q

In analyzing genetic crosses
_____________________ is the second generation

A

First Filial Generation or F1

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28
Q

In analyzing genetic crosses
____________ is the next generation

A

Second Filial Generation or F2

29
Q

Punnett square was named after ___________ who 1st devised this apporach

A

Reginald C. Punnett

30
Q

A tool used to predict the possible genotypes & phenotypes of offspring of resulting from a cross between 2 individuals

  • represents how genes in gametes join if they are on different chromosomes
A

PUNNETT SQUARE

31
Q

Mendel’s observation in his experiments:

  • producing the same phenotype
  • have the same trait as parent
    Ex: A true - breeding purple plant crossed itself will always produce offspring that are purple as well
A

TRUE - BREEDING

32
Q

Mendel’s observation in his experiments:

  • follows 1 trait & the self-crossed plants are HYBRIDS
  • true-breeding plant with 2 forms of a single gene trait are crossed
A

MONOHYBRID CROSS

33
Q
  • hides one expression of a trait, which appears when hybrids are self-crossed

Punnett Square or Monohybrid Cross

A

Monohybrid Cross

34
Q

In monohybrid cross, hybrids can hide one expression of a trait, which reappears when hybrids are self-crossed

How did this happen?

A

GAMETES DISTRIBUTE “ELEMENTEN”.
Paired set of ELEMENTEN separates gametes form. When gametes join at fertilization, the ELEMENTEN combine anew.

35
Q

Mendel’s first law, distribution of alleles of a gene into separate gametes during meiosis

A

LAW OF SEGREGATION

36
Q

Chromosomes of parent 1 and 2 replicate in _________
A. Anaphase
B. Metaphase
C. INTERPHASE
D. Monophase

A

INTERPHASE

37
Q

In ______ alleles segregates into gametes

Meiosis or Mitosis

A

MEIOSIS

38
Q

Used to determine the GENOTYPE of an individual showing a DOMINANT PHENOTYPE.
Ex: The pea plant is tall ( tall is dominant), is it heterozygous (Tt) or Homozygous (TT) ?

Punnett square or Monohybrid Cross or Test Cross

A

TEST CROSS (BACK CROSS)

39
Q
  • Pattern by which a GENETIC TRAIT/DISORDER IS PASSED FROM 1 GENERATION TO THE NEXT WITHIN A FAMILY
A

MODE OF INHERITANCE

40
Q

MODE OF INHERITANCE
A way that a trait is passed depends on whether:

A

A. The gene that determines is an autosome or sex chromosomes and,
B. Whether the allele is recessive or dominant

41
Q

MODE OF INHERITANCE includes

A
  1. AUTOSOMAL DOMINANT INHERITANCE
  2. AUTOSOMAL RECESSIVE INHERITANCE
  3. SEX - INHERITANCE
    a. Y - linked inheritance
    b. X - linked dominant inheritance
    c. X - linked recessive inheritance
42
Q
  • trait/disorder is caused by a DOMINANT ALLELE LOCATED ON 1 OF THE AUTOSOMAL CHROMOSOMES
  • a single copy of the dominant allele will exhibit the trait/disorder
A

AUTOSOMAL DOMINANT INHERITANCE

43
Q

Criteria in AUTOSOMAL DOMINANT INHERITANCE

A
  1. Males and females can be affected. (Male-to-male transmission can occur
  2. Males and females transmit the trait with equal frequency
  3. Successive generations are affected
  4. Transmission stops after a generation in which no one inherits the mutation
44
Q

For many autosomal dominant traits/disorders, affected individuals are HETEROZYGOUS. The HOMOZYGOUS dominant phenotype is either lethal or very rare

True or false

A

True

45
Q
  • trait/disorder is caused by a RECESSIVE ALLELE located on 1 of the autosomal chromosomes
  • 2 copies of the recessive allele (homozygous) to exhibit the trait or disorder
A

AUTOSOMAL RECESSIVE INHERITANCE

46
Q

Criteria for AUTOSOMAL RECESSIVE INHERITANCE

A
  1. Males and females can be affected
  2. Affected females and males can transmit the gene, unless it causes death before reproductive age
  3. The trait can skip generations
  4. Parents of an affected individual are heterozygous or have the trait.

Ex: albinism

47
Q

AUTOSOMAL RECESSIVE INHERITANCE

  • affected individuals are HOMOZYGOUS RECESSIVE. Carriers are heterozygous and asymptomatic

Ex: Albino

True or false?

A

True

48
Q
  • Pattern of inheritance of genetic traits/disorders that
    are located on the sex chromosomes
A

SEX - LINKED INHERITANCE

49
Q

SEX - LINKED INHERITANCE
- Involves genes located on the Y CHROMOSOMES & traits/disorders are rare because it has few genes
- Passed from male-to-male(father-to-sons)
- No affected females

A

Y-LINKED INHERITANCE

50
Q

EXAMPLE OF Y-LINKED INHERITANCE
- inability to conceive

A. MALE INFERTILITY
B. Y-LINKED CONGENITAL HYPOPLASIA
C. RETINITIS PIGMENTOSA 2 (RP2)

A

MALE INFERTILITY

51
Q

EXAMPLE OF Y-LINKED INHERITANCE
- impaired development of the adrenal glands

A. MALE INFERTILITY
B. Y-LINKED CONGENITAL HYPOPLASIA
C. RETINITIS PIGMENTOSA 2 (RP2)

A

Y-LINKED CONGENITAL HYPOPLASIA

52
Q

EXAMPLE OF Y-LINKED INHERITANCE
- progressive vision loss due to the degeneration of photoreceptor cells in the retina

A. MALE INFERTILITY
B. Y-LINKED CONGENITAL HYPOPLASIA
C. RETINITIS PIGMENTOSA 2 (RP2)

A

RETINITIS PIGMENTOSA 2 (RP2)

53
Q

SEX - LINKED INHERITANCE
- Recessive allele is located on the X CHROMOSOME
- Always expressed in MALES (inherited from heterozygote/ homozygote mother)
- Expressed in females if the CAUSATIVE ALLELES IS PRESENT IN 2 COPIES (inherited from affected father & affected heterozygote mother)
- Females are usually CARRIERS (heterozygotes) & asymptomatic)

A

X-LINKED RECESSIVE INHERITANCE

54
Q

EXAMPLE OF X-LINKED RECESSIVE DISORDERS
- rough, brown, scaly skin, an enzyme deficiency blocks removal of cholesterol from skin cells

A. ICHTHYOSIS
B. COLORBLINDNESS
C. HEMOPHILIA

A

ICHTHYOSIS

55
Q

EXAMPLE OF X-LINKED RECESSIVE DISORDERS
- affects an individual’s ability to perceive or distinguish certain colors

A. ICHTHYOSIS
B. COLORBLINDNESS
C. HEMOPHILIA

A

COLORBLINDNESS

56
Q

EXAMPLE OF X-LINKED RECESSIVE DISORDERS
- blood - clotting disorder

A. ICHTHYOSIS
B. COLORBLINDNESS
C. HEMOPHILIA

A

HEMOPHILIA

57
Q

SEX - LINKED INHERITANCE
- Dominant allele located on the X chromosome
- Expressed in FEMALES IN 1 COPY and they are more likely to be affected
- Much more severe effects in males
- Passed from MALE TO ALL DAUGHTERS, but to no sons

A

X-LINKED DOMINANT INHERITANCE

58
Q

X-LINKED DOMINANT DISORDERS
- neurological and developmental disorder

A. RETT SYNDROME
B. INCONTINENTIA PIGMENTI
C. CONGENITAL HYPERTRICHOSIS

A

RETT SYNDROME

59
Q

X-LINKED DOMINANT DISORDERS
- primarily affects the skin, hair, teeth, and nervous system

A. RETT SYNDROME
B. INCONTINENTIA PIGMENTI
C. CONGENITAL HYPERTRICHOSIS

A

INCONTINENTIA PIGMENTI

60
Q

X-LINKED DOMINANT DISORDERS
- werewolf syndrome, characterized by excessive hair growth over the body

A. RETT SYNDROME
B. INCONTINENTIA PIGMENTI
C. CONGENITAL HYPERTRICHOSIS

A

CONGENITAL HYPERTRICHOSIS

61
Q

INHERITANCE OF MORE THAN ONE GENE

Mendel’s 2nd law: States that for 2 genes on different chromosomes, the inheritance of 1 gene does not influence the chance of inheriting the other gene

A

LAW OF INDEPENDENT ASSORTMENT

62
Q

INHERITANCE OF MORE THAN ONE GENE

  • 2 genes and traits are followed

A. MONOHYBRID CROSS
B. DIHYBRID CROSS
C. TEST CROSS

A

DIHYBRID CROSS

63
Q
  • Charts that display family relationship and depicts which relatives have specific phenotypes and sometimes, genotypes
  • May also include molecular data, test results, and information on variants of multiple genes
A

PEDIGREES

64
Q

PEDIGREE ANALYSIS
 Skips a generation through carriers
 Both males and females are affected

A. Pedigree for an autosomal recessive trait/disorder
B. Pedigree for an autosomal dominant trait/disorder
C. Pedigree for a Y-linked trait/disorder
D. Pedigree for a X-linked recessive trait/disorder
E. Pedigree for a X-linked dominant trait/disorder

A

Pedigree for an autosomal recessive trait/disorder

65
Q

PEDIGREE ANALYSIS
 Does not skip a generation
 Both males and females are affected

A. Pedigree for an autosomal recessive trait/disorder
B. Pedigree for an autosomal dominant trait/disorder
C. Pedigree for a Y-linked trait/disorder
D. Pedigree for a X-linked recessive trait/disorder
E. Pedigree for a X-linked dominant trait/disorder

A

Pedigree for an autosomal dominant trait/disorder

66
Q

PEDIGREE ANALYSIS
 All males are affected

A. Pedigree for an autosomal recessive trait/disorder
B. Pedigree for an autosomal dominant trait/disorder
C. Pedigree for a Y-linked trait/disorder
D. Pedigree for a X-linked recessive trait/disorder
E. Pedigree for a X-linked dominant trait/disorder

A

Pedigree for a Y-linked trait/disorder

67
Q

PEDIGREE ANALYSIS
 Females are usually carriers (heterozygotes)
 Always expressed in males

A. Pedigree for an autosomal recessive trait/disorder
B. Pedigree for an autosomal dominant trait/disorder
C. Pedigree for a Y-linked trait/disorder
D. Pedigree for a X-linked recessive trait/disorder
E. Pedigree for a X-linked dominant trait/disorder

A

Pedigree for a X-linked recessive trait/disorder

68
Q

PEDIGREE ANALYSIS
 Expressed both in males and females
 Passed from male to all daughters, but to no sons

A. Pedigree for an autosomal recessive trait/disorder
B. Pedigree for an autosomal dominant trait/disorder
C. Pedigree for a Y-linked trait/disorder
D. Pedigree for a X-linked recessive trait/disorder
E. Pedigree for a X-linked dominant trait/disorder

A

Pedigree for a X-linked dominant trait/disorder