What does it mean if a trait is 'sex-linked'?
Why are males more likely to be affected by recessive sex-linked disorders?
Sex-linked traits are often more common in males than in females. Males more likely to express X-linked recessive traits compared to females because.
In a genetic cross where a mother is a carrier for Duchenne muscular dystrophy (an X-linked recessive disorder) and the father is unaffected, what is the probability that their son will be affected by the disorder?
Hemophilia (Xh) is a sex-linked recessive trait.
Important Note
BB and Bb males = bald
bb males = non bald.
Bb and bb females = non bald. BB females = bald
What is the sex and eye color of flies with the following genotype: X R Y ?
Hunter syndrome is a progressively debilitating recessive disorder that is inherited on the X chromosome.
A father without Hunter syndrome and an unaffected carrier mother have a child.
Which of the following statements is true?
In the fruit fly Drosophilia, eye color is sex-linked.
The allele for red eyes is dominant XW and the allele for white eyes is recessive Xw. A scientist crosses two red-eyed flies and notice that half of their male offspring have white eyes.
What are the genotypes of the parents?
Because all of the male offspring have white eyes, and white eyes are a recessive sex-linked trait, the male offspring's genotypes must be XwY. The only option for the father to have a normal phenotype is if his genotype is XWY
In order to have a normal phenotype, the mother must be either XWXW or XWXw
However, because a male offspring always inherits his X chromosome from his mother, she must be able to donate an Xw allele to her male offspring for them to have white eyes.
This leaves only one option for the mother's genotype: XWXw
Which of the following genotypes represents an individual who would be considered a carrier for baldness, an x-linked recessive trait?
Ellen and Patrick are planning to get married, but Ellen has a father who is a hemophiliac, an x-linked recessive trait, and she is concerned about having such a child herself. Ellen and Patrick are both normal and do not have the disease.
What is the probability that they will have a child that has hemophilia?
Muscular dystrophy is an x-linked recessive trait that causes the progressive weakening of the skeletal muscles. Unfortunately, mothers are responsible for passing this trait on to their sons. A mother who has muscular dystrophy marries a man who is normal.
What are the chances of this couple having a son who is affected?
Cat coat color is an X-linked trait.
Calico cats typically have patches of black, white, and orange on their coats as a result of X-inactivation. Most calico cats are female, but rarely a male calico will be born into a litter.
Which of the following could explain calico coat color in a male kitten?
An unknown disease is a sex-linked recessive trait. Bella is worried that she might have the disease and goes to a genetic counselor to find out. The counselor tells Bella that her mom does not have the disease, her dad does, and that the disease is associated with the Y chromosome.
What is the probability that Bella has the disease?
What are the expected phenotypes of the kids from a heterozygous A parent (IAi) and a heterozygous B parent (IBi)?
Type A:
Type B:
Type AB:
Type O:
What are the expected phenotypes of the kids from a type AB blood parent and a heterozygous A parent (IAi)?
Type A:
Type B:
Type AB:
Type O:
Brenda claims that Jose is not the father of her child, Steve. Brenda has Type IAi blood and Jose has Type IBi blood. The baby has Type ii blood.
What do you think?
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?
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?
Select all genotypes that represent Type B blood.
In pigs, fur color is codominant. When a pig is heterozygous, it is brown with white spots.
If a pig with brown fur (BB) mates with a pig with white fur (WW), what are the phenotypes of the offspring?
In pigs, fur color is codominant. When a pig is heterozygous, it is brown with white spots.
If a pig with brown fur (BB) mates with a pig with white fur (WW), what are the phenotypes of the offspring?
A puppy receives a black allele from mom and a white from dad. What color would the puppy be if the fur color follows the rules of incomplete dominance?
A plant receives one blue allele and one yellow allele from its parents. What color would the plant be if the leaf color follows the rules of incomplete dominance?
From these two heterozygous parents,
Show your work.
From these two heterozygous parents,
Show your work.
From these two heterozygous parents,
Show your work.
In rabbits, white coat color (CW) and black coat color (CB) are codominant, and both of these alleles are dominant over albino (c). Heterozygotes (CWCB) are spotted.
What are the expected phenotypes from the offspring of a heterozygous black coat rabbit (CBc) and a homozygous white coat rabbit (CWCW) ?
In a species of birds, blue feathers (B) are incompletely dominant to the gene for white feathers (W). Individuals that are heterozygous (BW) have blue-tipped feathers.
A bird with blue-tipped feathers is crossed with a white bird. What is the chance that the offspring will have blue feathers?
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 that their sons will be 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?
In a Punnett square for hemophilia, what does the genotype XHXh indicate about a female?
What is the probability that a son will have hemophilia if his mother is a carrier (XH Xh) and his father does not have hemophilia (XH Y)?
In a family where the mother is a carrier of hemophilia (an X-linked recessive disorder) and the father is healthy, what is the probability that their daughter will be a carrier of hemophilia?
Hemophilia is a recessive x-linked disorder. Which genotype represents a male with hemophilia?
If a woman whose father is bald and a man who is bald have a son and the woman's mother does not carry the allele for pattern baldness.
The probability that the son will inherit the allele for pattern baldness is -
When a heterozygous bald man marries a heterozygous non bald woman, the probability of bald and non sons.
If both the parents are heterozygous for this gene, what will be the probability of non-bald sons and non- bald daughters respectively?
BB and Bb males = bald
Bb and bb females = non bald
What is the sex and eye color of flies with the following genotype: X R X r ?
Select all genotypes that represent Type O blood.
Select all genotypes that represent Type AB blood.
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?
