EXTENSION OF MENDELIAN INHERITANCE(lesson 1) genetics Flashcards

1
Q

Prevalent alleles in a
natural population.

A

Wild-type alleles

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2
Q

more than one
wild-type allele may occur

A

Genetic polymorphism-

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3
Q

promote the
reproductive success of organisms in
their native environments.

A

Wild-type alleles

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4
Q

random mutations occur
in populations and alter preexisting
alleles. Called as such to distinguish
them from the more common wild-type
alleles

A

Mutant alleles-

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5
Q

usually cause a substantial decrease in the
expression of a functional protein supported by the analysis of many human genetic diseases.

A

Recessive mutant alleles

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6
Q
  • much less common than recessive
    mutant alleles.
A

Dominant mutant allele

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7
Q

is usually caused by a mutant
allele.

A

genetic disease

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8
Q

Three explanations account for most dominant mutant
alleles:

A

Gain-of-function mutation
* Dominant-negative mutation
* Haploinsufficiency.

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9
Q

*Change the gene or the protein encoded by a gene
so it gains a new or abnormal function.

A

Gain-of-function mutation

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10
Q

*Change a protein such that the mutant protein acts
antagonistically to the normal protein.

A

Dominant-negative mutations

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11
Q

The dominant mutant allele is a loss-of-function
allele.

A

Haploinsufficiency

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12
Q

used to describe patterns of
inheritance in which a heterozygote

  • An example in humans is polydactyly.
A

Haploinsufficiency

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13
Q

which an allele that is expected to cause
a particular phenotype does not.

A

INCOMPLETE PENETRANCE

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14
Q

Human pedigree for a dominant trait
known as

A

polydactyly

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15
Q

due to an autosomal
dominant allele—

A

Polydactyly

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16
Q

a single copy of this
allele is sufficient to cause this
condition.

A

autosomal
dominant allele

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17
Q

term used to describe the outcome of traits is
the degree to which the trait is expressed

A

Expressivity-

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18
Q

often due to environmental
influences and/or due to effects of modifier genes

A

INCOMPLETE PENETRANCE

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19
Q

The
phenotypic effects are dependent on
the temperature

A

Temperature-sensitive allele.

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20
Q

autosomal
recessive disease is caused by a defect in
a gene that encodes the enzyme
phenylalanine hydroxylase.

A

Phenylketonuria (PKU)

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21
Q

which is found in most protein-rich
foods,

A

phenylalanine,

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22
Q

detrimental traits including mental
impairment, underdeveloped teeth, and
foul-smelling urine.

A

Phenylketonuria (PKU)

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23
Q

A condition in which the phenotype is
intermediate between the corresponding
homozygous individuals.

A

INCOMPLETE DOMINANCE

24
Q

German botanist ____ first
observed this phenomenon in the color of the
flowers of the four-o’clock plant (Mirabilis
jalapa)

A

Carl Correns

25
Q

lack of
a functional protein required for pigmentation.

A

Heterozygote Advantage/ OVERDOMINANCE

26
Q

which the affected individual produces
an altered form of the protein hemoglobin, which
carries oxygen within red blood cells.

A

Sickle cell disease-

27
Q

This causes their red
blood cells to deform into a

A

sickle shape under
conditions of low oxygen concentration

28
Q

Individuals affected with sickle cell
disease are

A

homozygous for the HbS allele

29
Q

high frequency among human populations
that are exposed to malaria.

A

OVERDOMINANCE

30
Q

spends part of its life
cycle within the Anopheles mosquito and another part within the red blood
cells of humans who have been bitten by an infected mosquito.

A

malaria, Plasmodium,

31
Q

, are likely to rupture
when infected by this parasite, thereby preventing the parasite from
propagating.

32
Q

two
alleles are both expressed
in the heterozygous
individual

A

CODOMINANCE

33
Q

when a gene is located on the X
chromosome but not on the Y chromosome.

A

X-linked inheritance

34
Q

to indicate that males have a single copy of an X-linked gene

A

Hemizygous

35
Q

is that males are more likely to be
affected by rare, recessive X-linked disorders.

A

X-linked inheritance

36
Q

X-linked recessive, the allele causing
the disease is recessive and located on the X chromosome

A

Duchenne muscular dystrophy-

37
Q

refers to a gene that is found on one of the two types
of sex chromosomes but not on both.

A

Sex-linked gene-

38
Q

relatively few genes are located only on the
Y chromosome.

A

Holandric genes

39
Q

found in mammals.

40
Q

Its expression is necessary for proper
male development.

41
Q

which an allele is dominant
in one sex but recessive in the opposite sex.

A

Sex-influenced inheritance-

42
Q

controlled by sex hormones or by the pathway
that leads to male and female development

A

Sex-limited inheritance-

43
Q

The genes that affect sex-limited traits maybe

A

autosomal or X-linked

44
Q

are the presence of ovaries in

females and the presence of testes in males.

A

sex-limited traits

45
Q

which members of the
opposite sex have different morphological features.

A

Sexual dimorphism

46
Q

has the potential to cause the death of an
organism.

A

LETHAL ALLELES

47
Q

one that must be present for survival

A

Essential gene-

48
Q

not absolutely required for survival, although they
are likely to be beneficial to the organism.

A

Nonessential genes-

49
Q

some lethal alleles may kill an organism only
when certain environmental conditions prevail

A

Conditional lethal alleles-

50
Q

conditional lethal alleles
cause an organism to die only in a particular temperature range.

A

Temperature-sensitive (ts) lethal alleles-

51
Q

may also be identified when an individual is
exposed to a particular agent in the environment.

A

lethal alleles-

52
Q

People with a defect in the gene that encodes the ____ have a negative reaction to the
ingestion of ____.

A

enzyme glucose-6-phosphate dehydrogenase (G-6-PD)

fava beans

53
Q

lethal alleles act only in some individuals.

A

Semilethal alleles-

54
Q

multiple effects of a single gene

A

PLEIOTROPY

55
Q

all traits are affected by
the contributions of many genes.

A

GENE INTERACTIONS