In humans, males are ____ since they have two different sex chromosomes.
True or False. Sexual identity is determined by the sex chromosome make-up of an individual only.
If the ____ gene on the ____ chromosome is activated, hormones steer the human development along a male route.
Once the SRY gene begins to function, ____ cells begin to secrete anti-Mullerian hormone and ____ cells secrete testosterone.
Pseudohermaphroditism caused by 5-alpha reductase deficiency leads to a _____.
|A)||female exterior, male interior, and male genotype|
|B)||male exterior, female interior, and female genotype|
|C)||female exterior, female interior, and female genotype|
|D)||male exterior, male interior, and female genotype|
What would be the sex of an XXY individual?
PAR1 and PAR2 on both tips of the Y chromosome are _____.
|A)||male specific regions|
|C)||sites of deletions|
What is the function of SRY?
|A)||transcription factor gene that stimulates male development|
|B)||pseudoautosomal regions for meiosis|
|C)||gene for testosterone production|
|D)||cause of pseudohermaphroditism|
Evidence suggests that homosexuality is _____.
An affected male and a normal female had four children: two affected daughters and two normal sons. Each of the affected daughters (and their normal husbands) produced affected sons and affected daughters. The couple's normal sons married normal women and had all normal children. What is the most likely mode of inheritance for this trait?
The probability that a male inherited his Y chromosome from his maternal grandfather is _____.
A female whose father was colorblind marries a normal male whose father was also colorblind. What is the probability that their son will be colorblind?
A female whose father was colorblind marries a normal male whose father was also colorblind. What is the probability that their daughter will be colorblind?
A woman whose husband worked at the Chernobyl nuclear reactor gives birth to a hemophiliac son.
|A)||She should blame the reactor accident because the radiation caused the hemophilia.|
|B)||She should not blame the accident because she may carry the hemophilia allele.|
|C)||Her husband should sue for divorce because it cannot be his child.|
|D)||Further genetic tests should be done to determine who is at fault.|
|E)||Hemophilia is environmentally induced, not genetic.|
Which of the following genetic conditions is not sex-linked?
|D)||a and c|
A woman whose brother has hemophilia is concerned about passing this trait to her offspring. If this woman has a son, what is the risk that her son will have hemophilia?
Consider a sex-linked recessive trait. Which of the following crosses would produce males and females with different phenotypes?
|A)||homozygous normal female x normal male|
|B)||affected female x affected male|
|C)||affected female x normal male|
|D)||heterozygous normal female x affected male|
Can a male be a carrier for a sex-linked disease?
|A)||Yes, if the trait is recessive|
|B)||Yes, if the male's father and mother were carriers|
|C)||No, males have only a single copy of sex-linked genes|
|D)||No way to predict|
Males are ____ for X-linked traits.
Which of the following is incorrect for an X-linked recessive trait?
|A)||always expressed in the female|
|B)||passed from heterozygote or homozygote mother to son|
|C)||expressed in a female homozygote|
|D)||affected female has an affected father and an affected or heterozygous mother|
X-inactivation can account for individuals who _____.
|A)||are manifesting heterozygotes|
|B)||show a mosaic pattern of expression|
|C)||display a sex-limited trait|
|D)||a and b|
How many Barr bodies would be observed in the nucleus of an XXY individual?
Individuals with three copies of most autosomes do not survive. Individuals with an extra X chromosome, however, survive with relatively mild (compared to autosomal abnormalities) consequences. Why?
|A)||The X chromosome contains few genes while autosomes contain a large number.|
|B)||The extra X chromosome(s) are inactivated.|
|C)||The X chromosome determines sex only.|
|D)||None of the above|
Calico cats have large patches of coat color. What can we conclude about the timing of X-inactivation?
|A)||It occurred early.|
|B)||It occurred late.|
|C)||It occurred both early and late.|
|D)||No relationship exists.|
The majority of calico cats are female. However, a few rare males are observed. What is the genotype of a male calico cat?
Pattern baldness is a ____ trait.
A ____ affects body parts or functions present in only one gender.
|B)||trait determined by mitochondrial DNA|
Beard growth and pregnancy in humans are examples of ____ traits.
A woman who carries the cystic fibrosis gene and her homozygous normal husband have a child with cystic fibrosis. How can this occurrence be explained?
|D)||none of the above, infidelity is the only plausible explanation|
Prader-Willi Syndrome and Angelman Syndrome are both associated with deletions of the same bands from the long arm of chromosome 15. However, the physical expression associated with each disorder is very different. This is an example of _____.
Each of the following statements describes Y-linked inheritance EXCEPT:
|A)||Traits are transmitted from father to son.|
|B)||There are no affected females.|
|C)||Traits that involve infertility are not transmitted.|
|D)||Traits are transmitted from mother to son.|
A human male inherits X-linked traits from _____.
|A)||his mother only|
|B)||his father only|
|C)||both his mother and father|
|D)||Males do not have X-linked traits.|
Which item correctly represents a male who inherits an X-linked dominant trait?
A human female inherits X-linked traits from _____.
|A)||her mother only|
|B)||her father only|
|C)||both her mother and father|
|D)||Females do not have X-linked traits.|
Which item correctly represents a female who is homozygous recessive for an X-linked trait?