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Cytogen > Extension Of Mendel’s Law > Flashcards

Extension Of Mendel’s Law Flashcards

1
Q

Mendelian inheritance describes inheritance patterns that obey two laws

A

Law of segregation
Law of independent assortment

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2
Q

Simple Mendelian inheritance involves

A single gene with two different____
Alleles display a simple ____\ relationship

A

alleles
dominant/recessive relationship

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3
Q

Prevalent alleles in a population are termed____

A

wild-type alleles

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4
Q

These typically encode proteins that
Function normally
Are made in the right amounts

A

wild-type alleles

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5
Q

Alleles that have been altered by mutation are termed_____

A

mutant alleles

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6
Q

These tend to be rare in natural populations

A

mutant alleles

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7
Q

They are likely to cause a reduction in the amount or function of the encoded protein

A

Mutant alleles

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8
Q

mutant alleles are often inherited in a_____ fashion

A

recessive

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9
Q

Drosophila dominant allele

A

Red eyes
Normal wings

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10
Q

Drosophila recessive allele

A

White eyes
Miniature wings

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11
Q

_____diseases are caused by mutant alleles

A

Genetic

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12
Q

This prevents the allele from producing a fully functional protein

A

Mutation

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13
Q

In a simple dominant/recessive relationship, the_____ allele does not affect the phenotype of the heterozygote

A

recessive

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14
Q

how can the wild-type phenotype of the heterozygote be explained?

There are two possible explanations:

A

50% of the normal protein is enough to accomplish the protein’s cellular function

The heterozygote may actually produce more than 50% of the functional protein

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15
Q

______ are those that are absolutely required for survival

The absence of their protein product leads to a______ phenotype

A

Essential genes

lethal

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16
Q

It is estimated that about____ of all genes are essential for survival

A

1/3

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17
Q

_____ genes are those not absolutely required for survival

A

Nonessential genes

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18
Q

is one that has the potential to cause the death of an organism

A

lethal allele

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19
Q

These alleles are typically the result of mutations in essential genes

They are usually inherited in a recessive manner

A

Lethal allele

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20
Q

Many_____ alleles prevent cell division
These will kill an organism at an early age

A

lethal

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21
Q

Some lethal alleles exert their effect later in life

_______ disease
Characterized by progressive degeneration of the nervous system, dementia and early death

The age of onset of the disease is usually between 30 to 50

A

Huntington

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22
Q

________ alleles may kill an organism only when certain environmental conditions prevail

A

Conditional lethal alleles

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23
Q

Temperature-sensitive (ts) lethals
A developing Drosophila larva may be killed at____
But it will survive if grown at____

A

30 C

22 C

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24
Q

Kill some individuals in a population, not all of them

A

SEMI LETHAL ALLELES

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25
Q

Environmental factors and other genes may help prevent the detrimental effects of_______ genes

A

semilethal genes

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26
Q

A_____ allele may produce ratios that seemingly deviate from Mendelian ratios

An example is the “creeper” allele in chicken

A

lethal allele

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27
Q

In ________ the heterozygote exhibits a phenotype that is intermediate between the corresponding homozygotes

A

incomplete dominance

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28
Q

Three or more different alleles

A

multiple alleles

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29
Q

coat color in rabbits
Has ____different alleles

A

Four

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30
Q

Partial defect in pigmentation

A

Cch (chinchilla pattern of coat color)

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31
Q

Pigmentation in only certain parts of the body

A

ch (himalayan pattern of coat color)

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32
Q

Lack of pigmentation

A

c (albino)

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33
Q

The himalayan pattern of coat color is an example of a ______conditional allele

A

temperature-sensitive

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34
Q

The enzyme encoded by this gene is functional only at low temperatures

Therefore, dark fur will only occur in cooler areas of the body

This is also the case in the Siamese pattern of coat color in cats

A

temperature-sensitive conditional allele

35
Q

______, the opposite phenotype occurs

The coat in the cooler parts of the body is light-colored

The allele in this case is likely to be cold-sensitive

Its enzymatic product does not work well at lower temperatures

A

Brown Swiss

36
Q

The ABO blood group provides another example of____ alleles

A

multiple

37
Q

It is determined by the type of antigen present on the surface of red blood cells

A

ABO blood group

38
Q

are substances that are recognized by antibodies produced by the immune system

A

Antigens

39
Q

Alleles /A and /B are

A

codominant

40
Q

Allele i is____ to both /A and /B

A

recessive

41
Q

is the phenomenon in which a heterozygote is more vigorous than both of the corresponding homozygotes

A

Overdominance

42
Q

Overdominance is also called

A

heterozygote advantage

43
Q

Where being heterozygous gives you the best chance of having children and living the best quality of life!

A

heterozygote advantage (overdominance)

44
Q

Example = Sickle-cell anemia
Autosomal____ disorder
Affected individuals produce abnormal form of hemoglobin

A

recessive

45
Q

Sickle cell

Two alleles:
____→ Encodes the normal hemoglobin, hemoglobin A
____→ Encodes the abnormal hemoglobin, hemoglobin S

A

HbA

HbS

46
Q

is caused by a protozoan, Plasmodium

A

Malaria

47
Q

In some instances, a dominant allele is not expressed in a heterozygote individual

A

Incomplete dominance

48
Q

Example = Polydactyly

Autosomal_____ trait
Affected individuals have additional fingers and/or toes

A

dominant

49
Q

A_____ copy of the polydactyly allele is usually sufficient to cause this condition

In some cases, however, individuals carry the dominant allele but do not exhibit the trait

A

single

50
Q

The term indicates that a dominant allele does not always “penetrate” into the phenotype of the individual

A

Incomplete Penetrance

51
Q

The measure of penetrance is described at the population level

If 60% of heterozygotes carrying a dominant allele exhibit the trait allele, the trait is 60% penetrant

A

Incomplete penetrance

52
Q

is the degree to which a trait is expressed

A

Expressivity

53
Q

In the case of polydactyly, the number of digits can vary

A person with several extra digits has____ expressivity of this trait

A person with a single extra digit has___ expressivity

A

high

low

54
Q

The molecular explanation of _____ and ______may not always be understood

A

expressivity and incomplete penetrance

55
Q

In most cases, the range of phenotypes is thought to be due to influences of the

A

Environment and/or
Other genes

56
Q

_______ conditions may have a great impact on the phenotype of the individual

A

Environmental

57
Q

Phenylketonuria
Autosomal_____ disorder in humans
Caused by a defect in the gene that encodes the enzyme phenylalanine hydroxylase

A

recessive

58
Q

PKU patient

Their diet is essentially_______-free

A

phenylalanine

59
Q

Some genes can be altered or modified by the effects of one or more other genes.
This effect is called_____

A

epistasis

60
Q

The inheritance pattern of certain traits is governed by the sex of the individual

These traits are of 3 main types

A

8.1 Sex-linked
8.2 Sex-influenced
8.3 Sex-limited

61
Q

Sex Determination
Humans have 46 chromosomes.
2 of those 46 chromosomes are called_____

A

sex chromosomes

62
Q

The other 44 chromosomes are called____.

A

autosomes

63
Q

Most of your chromosomes are____ are chromosomes that determine your traits.

A

autosomes

64
Q

can determine traits as well, but they also determine gender or sex.

A

Sex chromosomes

65
Q

Sex chromosomes can either be X or Y.

If an individual’s sex chromosomes are both X chromosomes, that person will be a____.
If an individual’s sex chromosomes are X and Y, that person will be a____

A

female

male.

66
Q

Traits controlled by genes on the sex chromosomes are called

A

sex-linked traits.

67
Q

Because______ have only one X chromosome, they are affected by recessive traits found on the X chromosome more than females.

______are less likely to express a recessive trait on an X chromosome, because the other X chromosome may have a dominant allele.

A

males

Females

68
Q

How are Sex-linked traits inherited?

This would be the result from a cross between a female_____ (XBXb) for color blindness and ____ male (XBY).

½ of the children would be normal
½ would either be color blind or be carriers

A

carrier

normal

69
Q

Hemophilia is another ______ trait that causes delayed blood clotting.

A

sex-linked trait

70
Q

Most sex-linked traits like color blindness and hemophilia affect____ more than_____.

A

males

females

71
Q

Calico cats are always______ because the gene for coat color is on the X chromosome.

If a_______ is heterozygous, it will be a calico cat.

A

females

72
Q

Male pattern baldness is technically an autosomal trait, but it acts like a_____ trait

A

sex-linked trait.

73
Q

Eye color in Drosophila Fruit flies is a _____ trait

A

sex-linked trait

74
Q

Calico Cats
_____can either be black or orange
______can be black, orange, or calico.

This is caused by one of the X chromosomes becoming inactive in female cats.

A

Males

Females

75
Q

Traits where an allele is dominant in one sex but recessive in the opposite sex

Thus, _____ is a phenomenon of heterozygotes

A

Sex-influenced Traits

76
Q

Male Pattern Baldness
The gene for baldness is recessive in____, but dominant in____.

A

females

males

77
Q

______can either be heterozygous or homozygous dominant.

______must be homozygous recessive to be bald.

A

Males

Females

78
Q

Traits that occur in only one of the two sexes

A

Sex-limited Traits

79
Q

Type of trait

Breast development is normally limited to females

A

Sex-limited Traits

80
Q

Type of trait

Beard growth is normally limited to males

A

Sex-limited Traits

81
Q

Sex-limited Traits

Hen-feathering is controlled by a dominant allele expressed in ____

Cock-feathering is controlled by a recessive allele only expressed in____

A

both sexes

males

82
Q

occur when two or more different genes influence the outcome of a single trait

A

Gene interactions

83
Q

The term_____ describes the situation in which a gene Can porns mask the phenotypic effects of another gene

A

epistasis

84
Q

_______ often arise because two (or more) different proteins participate in a common cellular function

A

Epistatic interactions

Cytogen (34 decks)

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