Genetics: Patterns of Inheritance Flashcards
The following results were observed from a mating between two black and white speckled cats: 5 black cats, 12 black and white speckled cats, and 4 white cats. Which of the following best describe the relationship between alleles of the coat color gene?
a) Linked
b) Mendelian
c) Polygenic
d) Codominance
e) Incomplete dominance
d) Codominance
Which of the following terms best describes a situation in which heterozygotes demonstrate a phenotype which is intermediate between the homozygotes?
a) Hybrid dominance
b) Incomplete dominance
c) Blended dominance
d) Limited dominance
e) Codominance
b) Incomplete dominance
The red blood cells from a person with AB blood type exhibit which of the following phenotypes?
a) None of these answers are correct.
b) Both the ‘A’ and ‘B’ phenotype in each red blood cell
c) The ‘A’ phenotype
d) Either the ‘A’ or ‘B’ phenotype in separate red blood cells
e) The ‘B’ phenotype
b) Both the ‘A’ and ‘B’ phenotype in each red blood cell
Incomplete dominance governs the pigment gene of a flower. A mating between heterozygotes yields the following phenotypic ratio: 15 red flowers, 32 pink flowers and 14 white flowers. Which of the following best describes the situation?
a) The heterozygotes were red.
b) The flower pigment gene is defined by multiple alleles.
c) The flower pigment gene is defined by a pink and red allele.
d) The results comply with Mendelian predictions.
e) The flower pigment gene is defined by a red and a white allele.
e) The flower pigment gene is defined by a red and a white allele.
Which of the following is not an example of phenotypic variability?
a) Two PJS patients have regular colonoscopies every year. Each year, patient A has about ten to twelve polyps removed from his gastrointestinal tract. Patient B, on the other hand, sometimes has one polyp removed, sometimes has two polyps removed, and many times the doctors don’t find any polyps during the annual colonoscopy.
b) The penetrance of RP11 is about 60-70%.
c) A female patient who has the causative allele for RP11 experiences visual field loss and begins to lose her night vision as a teenager. She continues to lose her vision throughout her twenties. By the time she’s 35, she is considered to be legally blind.
d) All of these are examples of phenotypic variability.
e) A boy with PJS has dark spots around his mouth and lips and on his fingers, but no polyps. His sister who also has PJS has a large number of gastrointestinal polyps, but no dark spots around her mouth or on her fingers.
c) A female patient who has the causative allele for RP11 experiences visual field loss and begins to lose her night vision as a teenager. She continues to lose her vision throughout her twenties. By the time she’s 35, she is considered to be legally blind.
The extent to which a trait or condition is expressed is called what?
a) a syndrome
b) expressivity
c) phenotypic variability
d) severity
e) penetrance
b) expressivity
What is a syndrome?
a) a group of genetic factors that occur together
b) a range of different phenotypes
c) any trait or group of traits that is mainly determined by genetic factors
d) a grouping of recognizable characteristics that occur together and have a common cause
e) any genetic trait that results in a medical condition
d) a grouping of recognizable characteristics that occur together and have a common cause
A geneticist is studying a rare, autosomal dominant syndrome that is characterized by the following three hallmarks: a significantly increased risk for cancer, exceptional height, and early hearing loss. If the syndrome is 70% penetrant, what does this mean?
a) on average, people who have this syndrome will develop 70% of the hallmarks that characterize the syndrome
b) each child of an affected parent has a 70% chance of also developing the syndrome
c) the life expectancy of people with this syndrome is only 70% of the average human life span
d) a person who has the causative allele has a 70% chance of developing the syndrome
e) a person who has the causative allele has a 70% lifetime risk for cancer
d) a person who has the causative allele has a 70% chance of developing the syndrome
Which of the following statements is true?
a) Autosomal dominant conditions rarely show very much phenotypic variability.
b) Only certain genetic conditions have incomplete penetrance.
c) If a genetic condition shows variable expressivity, it cannot also have incomplete penetrance.
d) If a genetic condition shows variable expressivity, then it must also have incomplete penetrance.
e) All autosomal dominant genetic conditions sometimes skip a generation.
b) Only certain genetic conditions have incomplete penetrance.
Generally speaking, what are the odds that an autosomal dominant condition will be passed from an affected individual to their child?
a) 0%
b) 100%
c) It’s impossible to know.
d) 25%
e) 50%
e) 50%
A criss-cross inheritance pattern is seen in what type of genetic inheritance?
a) autosomal recessive inheritance
b) A criss-cross inheritance pattern is not associated with any specific type of genetic inheritance.
c) complex inheritance
d) autosomal dominant inheritance
e) sex-linked inheritance
e) sex-linked inheritance
A scientist is studying an animal and determines that a gene is located on autosome two. It controls antler production in the male animals. This is an example of a
a) Sex-linked trait
b) Sex-limited trait
c) Carrier trait
d) Dominant trait
e) Recessive trait
b) Sex-limited trait
Which of the following statements are true?
I. A human with two X chromosomes and a Y chromosome is male.
II. A human with one X chromosome is female.
III. All children of a color blind woman and a man who is not color blind will carry a color blind allele.
a) I, II and III
b) II
c) I
d) I and II
e) II and III
a) I, II and III
Hemophilia is an X-linked recessive trait. Consider a cross between a woman who is a carrier and a man who suffers from hemophilia. Which of the following statements are true?
I. All sons of these parents will be a hemophiliac.
II. Sons who suffer from hemophilia received the hemophilia allele from their mother.
III. Half of the daughters of this cross are predicted to be hemophiliacs.
a) I
b) III
c) I and II
d) II
e) II and III
e) II and III
Alleles A and B are linked on chromosome 1. Alleles C and D are linked on chromosome 2. If a crossover event does not occur between either set of genes, which gamete genotype could NOT be produced by an individual heterozygous at each locus.
a) a-b; c-d
b) A-B; C-d
c) A-B; C-D
d) a-b; C-D
e) A-B; c-d
b) A-B; C-d
