What does it mean if a trait is 'sex-linked'?
In humans, hemophilia (h) is a sex-linked recessive trait. If a female who is a carrier for hemophilia marries a male with normal blood clotting (H), what is the probability of having a son with hemophilia?
In cats, coat color is determined by an allele found on the X chromosome. The black allele is codominant with the orange allele. Individuals who are heterozygous have a mixed coat color called “Calico”.
If a female cat who is homozygous for black mates with an orange male, what is the probability of having a male Calico cat?
Achondroplasia is a genetic disorder caused by a dominant allele (A). The recessive allele leads to normal height (a). A heterozygous combination results in dwarfism, while a homozygous dominant combination is lethal and results in the death of the individual.
If two parents with dwarfism have children, what is the expected outcome of their cross?
Lethal: out of 4
Dwarfism: out of 4
Normal: out of 4
Why are males more likely to be affected by recessive sex-linked disorders?
Duchene muscular dystrophy is a sex linked trait. A not having this disease is dominant (N) to having this disease (n). A mother who is a carrier for this disease (XNXn) mates with a father that is not affected (XNY) in the cross below.
Based on the Punnett square for the sex linked trait, of males will be affected, and of the females will be affected.
In a Punnett square for hemophilia, what does the genotype XNXn indicate about a female?
Important Note
BB and Bb males = bald
bb males = non bald.
Bb and bb females = non bald. BB females = bald
In cats, coat color is codominant AND it is an X-linked trait. Meaning coat color is ONLY carried in the X chromosome.
Possible genotypes and phenotypes for females and males are shown in the table below.
Which table shows the expected phenotypes of offsprings resulting from a cross between a Female Calico cat and a Male Orange cat?
Select all genotypes that represent Type B blood.
The ABO blood group has several alleles, so why does each person only have two of them?
Two men claim that they are the father of one little boy (Frank). A blood test was done to see if either one of the men could POSSIBLY be the father. The first man, Dwight, has Type IAi (A) blood. The second man, Robert, has Type ii (O) blood. The little boy has Type IAIB (AB) blood and the mother, Angela, also has Type IAIB (AB) blood.
Who is the father of the little boy?
A father is heterozygous for his type IBi blood (BO) and the mother has type ii (OO) blood.
What are the possible blood types of babies born from this couple?
In a type of fish, scale color is codominant. Fish with blue scales (BB) crossed with fish with yellow scales (YY) produce offspring with blue-and-yellow scales (BY).
If a blue-scaled fish (BB) is crossed with a yellow-scaled fish, what are the expected phenotypes of their offspring?
If a pig with brown fur (BB) mates with a pig with white fur (WW), what are the phenotypes of the offspring?
Hydrangeas are beautiful shrubs that grow in a variety of forms. Many hydrangeas originally hail from Asia and there are some natives in the Americas as well as shown below.
Hydrangeas with the genotype HBHB are blue. Those with the genotype HYHY are yellow. Others with the genotype HBHY have a combination of the blue and yellow flowers.
Based on the information about the hydrangeas, which statement is true?
In plants known as "four o' clocks", the allele for the dominant red flower color is Incompletely Dominant over the allele for white flowers. A gardener wants to determine which of the following Punnett squares shows a cross between a heterozygous pink-flower plant and another heterozygous pink-flowered plant.
A model of the color patterns in rabbits is shown below.
Which Punnett square will produce a 50% spotted and a 50% white coat rabbits?
In a species of birds, blue feathers (FB) are incompletely dominant to the gene for white feathers (FW). Individuals that are heterozygous (FBFW) have blue-tipped feathers.
A bird with blue-tipped feathers is crossed with a white bird. Complete the sentences below for the predicted outcome of offspring produced.
The blue-tipped feathers genotype is and the white bird genotype is .
When these two birds are crossed, will be blue-tipped, and will be white.
Body color for horses is determined by two Incompletely dominant alleles: brown (BB) and cream (BC). When a horse is heterozygous for body color, it is described as palomino (BBBC).
What is the expected phenotypic ratio if two palomino horses mate?
Normal vision: XN
Colorblindness: Xn
Which genotype represents a male with normal vision?
The woman who is colorblind marries a man with normal vision. What is the probability of having a son who is colorblind?
Colorblindness is more common in males than in females because....
Liam and Allie are planning to have their first child. Liam is colorblind and concerned that he will pass this trait on to their child. Allie has normal vision. Their first child, a baby boy, is color-blind.
What is Allie's genotype?
Liam and Allie are planning to have their first child. Liam is colorblind and concerned that he will pass this trait on to their child. Allie has normal vision. Their first child, a baby boy, is color-blind.
What is the probability that they will have a daughter who is color-blind?
If a woman who is a carrier for colorblindness has a son, what is the probability that he will be colorblind?
Which Punnett square shows a 25% chance of the son having hemophilia?
Which cross results in a 50% chance of the daughter being a carrier for hemophilia?
A woman who is a carrier (XBXb) for Baldness mates with a man who is Bald (XbY), a recessive disease.
What percentage of their offspring will be carriers for baldness?
Show your work.
A woman who is a carrier (XBXb) for baldness mates with a man who is bald (XbY), a recessive disease.
What percentage of their offspring will be bald?
Show your work.
If two heterozygous agouti mice are crossed, what percentage of offspring will NOT survive?
What is the phenotypic ratio of the surviving mice from the cross above?
If a homozygous black mouse is crossed with a heterozygous agouti mouse, what percentage of offspring will be heterozygous?
Select all genotypes that represent Type O blood.
Select all genotypes that represent Type AB blood.
