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43 Cards in this Set
- Front
- Back
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Microphthalmia is a condition that causes chickens to have very small eyes, but it only appears in hens. The condition is autosomal recessive. Microphthalmia is sex-influenced and not sex-limited because |
both sexes have eyeballs |
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The probability that a boy whose mother is heterozygous for an X-linked trait inherits the recessive allele is |
1/2 |
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X-linked genes have different patterns of expression in females and males because |
males have only one copy of these genes |
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Imprinting affects the phenotype when |
one allele is imprinted and the other is inactivated or deleted |
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In humans, if the SRY gene is not expressed, the unspecialized gonads develop into |
ovaries |
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Two unusual type of people who led researchers to discovery of the SRY gene were |
XX males and XY females |
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Human males and females are genetically equivalent because |
one of a female's two X chromosomes is inactivated |
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In cattle, mahogany spots are dominant in males and recessive in females. This trait is |
sex-influenced |
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Imprinting disorders illustrate |
epigenetics |
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Indifferent gonads develop |
during the fifth week of prenatal development |
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The pseudoautosomal regions of the Y chromosome correspond to |
counterparts on the X chromosome |
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An allele that is dominant in one sex but recessive in the other is |
sex-influenced |
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A gene on the Y chromosome that determines maleness is |
SRY |
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In genomic imprinting, the expression of a genetic disorder depends on |
which parent transmits the disease-causing allele |
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Amed has scaly skin due to the X-linked recessive condition icthyosis. He is _______ for the trait.
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hemizygous |
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Eight-year-old Rhapsody has just learned that her younger brother Clyde is colorblind. Although she knows she has color vision because her cat Juice is clearly orange, and she reads that nearly all people with colorblindness are boys, she is concerned about her own sons one day. If she is a carrier for colorblindness, then the risk that a son of hers is colorblind is |
1/2 |
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Cliff has colorblindness and icthyosis, which causes scaly skin. Both traits are X-linked recessive. The probability that he transmits both traits to his sons is |
0 |
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A human cell with two Barr bodies and no Y chromosome is from |
a female with three X chromosomes |
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Human males are the _______ sex |
heterogametic |
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In female mammals |
the paternally inherited X chromosome is shut off in some cells |
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In males, genes on the X chromosome are |
expressed |
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X inactivation is controlled by |
the XIST gene |
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Femaleness or maleness is genetically set at |
conception |
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The male-specific region of the Y chromosome |
has all of the above |
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Chloe has the scaly skin condition icthyosis, which is X-linked recessive. Which of the following is most likely true? |
Her mother was a carrier and her father was affected |
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Sean has congenital generalized hypertrichosis, an X-linked dominant condition that produces dense hair on the face and upper body. He can pass this trait |
definitely to a daughter and definitely not to a son |
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Number of eggs laid per week and milk yield are traits that are |
sex-limited |
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Tamryn has a son who has Duchenne muscular dystrophy, which is inherited as an X-linked recessive trait. At a molecular level, the disease is due to lack of the protein dystrophin. Tamryn participates in a study to look at dystrophin levels in various muscles, so has cells sampled from 10 different muscles. Some cells make dystrophin, and some do not. An explanation for this finding is that |
the X chromosome that bears the mutation is turned on in some cells but off in others |
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A male with a missing SRY gene would be phenotypically a |
female |
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Renfrew is a male boa constrictor. He has two copies of a sex chromosome called a Z chromosome. Renfrew is a member of the __________ sex |
homogametic |
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Unspecialized gonads are |
paired structures in the embryo that can develop as either male or female, depending on the hormones secreted into the uterine environment |
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X-linked dominant traits are typically expressed |
much more severely in males because they have only one X chromosome |
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A human male inherits |
one X from his mother and his father's Y |
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Human females are the _______ sex. |
homogametic |
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A carrier of an X-linked recessive trait who experiences the phenotype is called a |
manifesting heterozygote |
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The probability that the daughter of a woman with a dominant disease-causing allele on the X chromosome and a normal male will be affected with the disorder is |
1/2 |
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A daughter can inherit an X-linked recessive disorder if |
her mother is a carrier and her father has the disorder |
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Prader-Willi and Angelman syndromes both arise from the same area of chromosome 15, illustrating |
genomic imprinting |
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The Y chromosome was challenging to sequence because |
the sequence has many sites of high symmetry called palindromes |
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Marbles is a calico cat with a Manx tail. She wants to have kittens with a male calico, but can't seem to find one. Alas, male calicos are rare; the only ones have the sex chromosome constitution XXY. Male calicos are therefore rare because |
most male cats have only one X chromosome, so it cannot be shut off |
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A gene that determines the heaviness of a man's beard is |
sex-limited |
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A daughter can inherit an X-linked recessive disorder when her father is affected and her mother is a carrier. |
true |
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A healthy man and a healthy woman have a son with Lesch-Nyhan syndrome, an X-linked recessive trait. What are the chances that a daughter of this couple will inherit Lesch-Nyhan syndrome? |
0 |
