In a cross between two strains that are true breeding for purple and white flowers, the F2 phenotypic ratio would be _____ if the flower color phenotype exhibits incomplete dominance
1/4 purple; 1/4 white; and 1/2 lavender
In four-o'clock plants, red flower color is dominant to white flower color. However, heterozygous plants have a pink color. If a pink flowered plant is crossed with a white flowered plant, what will be the phenotypic ratios of their offspring?
1/2 pink, 1/2 white
Hen feathering in chickens show what type of inheritance
sex limited
Epistasis is
when one gene can mask the expression of a second gene
Sex-influenced inheritance differs from sex-limited inheritance in which of the following ways?
Expression of the phenotype occurs only in one sex in sex-limited inheritance, but not in sex-influenced inheritance
A man has a color blind mother. He marries a genotypically normal woman. What is the probability that his first son will be colorblind?
0%
What disease is though to confer heterozygote advantage with respect to tuberculosis?
Tay Sachs
Two curly-winged Drosophilia are mated and produce 973 curly and 464 wild-type offspring. What is the genetic basis for these results?
A lethal allele
Phenylketonuria in humans in an example of
an environmental-influenced trait
In human blood groups, the fact that an individual can have an AB blood type in an example of
codominance
How did Bateson and Punnett's work with comb morphology in chickens differ from the dihybrid work of Mendel?
Their F2 offspring displayed 4 unique phenotypes, not the four combinations of two phenotypes expected in a Mendelian cross
An individual with type A blood and an indivual with type B blood mate and have offspring. What blood type is not possible in their offspring?
All blood types are possible
In a dihybrid cross of two heterozygous individuals, you expect a 9:3:3:1 phenotypic ratio in the offspring, but observe a ratio of 9:7. What is the most likely explanation?
Epistatic interaction of the two genes
Sickle-cell anemia in humans is an example of
heterozygous advantage
The coat characteristics of Siamese cats and Himalayan rabbits, where proteins in the extremities function differently than in the other parts of the body is an example of
Temperature-sensitive allele
If a geneticist describes a trait as being 70% penetrant, what would they mean?
Only 70% of the individuals who carry the trait express the trait
In the ABO blood system, which is the universal receiver?
AB
Temperature-sensitive alleles are examples
conditional lethal alleles
In an epistatic interaction, the genes must be located on the same chromosome
False
At the molecular level, which of the following best explains heterozygous advantage and over dominance?
A heterozygous individual can produce more varieties of homodimer proteins
The alleles produce two different proteins with slightly different functions
The proteins produced by the alleles may provide a broader range of environmental tolerance, such as te
If an allele is dominant in one sex and recessive in another, it is an example of
sex-influenced inheritance
A woman is heterozygous for the recessive X-linked gene for Lesch-Nyhan syndrome. What proportion of her daughters will be carriers for the trait if their father is not affected?
50%
If the frequency of color blind X chromosomes is .05, what is the frequency of color blind males?
5%
Male-pattern baldness is a sex-linked trait in humans
False
For a certain trait a heterozygous individual has a selective advantage than a homozygous dominant or homozygous recessive individual. This is called___
over dominance
A heterozygote possesses a phenotype that is intermediate between the homozygous dominant and homozygous recessive phenotypes. This is most likely an example of
incomplete dominance
A woman who is heterozygous for pattern baldness marries a man who is nonbald. Which of the following would be true of their offspring?
All the females would be nonbald, 1/2 of the males would be bald