PKU is a recessive disorder based on a single mutant gene. Consider that Noor is a carrier, but her partner Hamza has never had an incidence of PKU show up in his family history, which dates back to four generations. What is the likelihood their first child might develop PKU according to their genetics counselor?   a)    100%!   b)    50%   c)

Clark Kent and Lois Lane Kent are about to have a (Super) baby. As Superman, Clark possesses amazing traits, including heat-ray vision. Assume that this is: a) a dominant trait, and b) carried on the X chromosome. If Clark and Lois have a boy or a girl, what is the probability that they will possess their father's amazing abilities? (Remember: females have XX chromosomes, while males have XY chromosomes. The Y chromosome doesn’t carry any of the genes on the X chromosome).              X H = Superman’s heat-ray vision allele on his X chromosome             Y = Superman’s Y chromosome             X h = Lois’s normal vision allele on her X chromosome

In humans, one type of red-green colorblindness (n) is sex-linked and recessive. A) A woman who is a carrier marries a man with normal vision. What is the chance of having color-blind daughters? Color-blind sons? B) A heterozygous woman and a color-blind man marry. What is the chance of having color-blind daughters? Color-blind sons?

In humans, albinism (lack of skin pigment) is an autosomal recessive trait. The first child of two normally pigmented parents is an albino. Which of the following is true about this family? SELECT ALL THAT ARE CORRECT. A) Their first child (described above) has a homozygous recessive genotype B) The next child born to this couple has a 25% chance of being albino. C) If the next child born to this couple is male, he has a greater chance of being albino. D) The parents are both heterozygous for albinism. E) The probability of their second child being albino is 0% F) If the second and third child born to this couple are albino, the fourth child has 100% chance of also being albino.

How is it possible Jonathan has the dominant disorder, Huntington’s Disease, if none of his family had it?   a) The mutant allele remained ‘hidden’ in previous generations. b) He is homozygous for mutant huntingtin alleles unlike his grandparents, who are clearly heterozygous for the condition. c) The appearance of Huntington Disease in him might be the result of a new mutation appearing during his lifetime. d) His parents and grandparents were ashamed to admit they had it.

Stacey and Rishi are expecting fraternal twins, a boy and a girl. Stacey and Rishi have normal vision, but both of their fathers are colour vision deficient (CVD, a X-linked recessive trait). a) Draw a pedigree for their family b) Complete a Punnett square to show the cross between Stacey and Rishi. c) What is the probability that the baby will be a girl with CVD? d) What is the probability that the baby will be a boy with normal vision?

All of the following are reasons that Mendel chose the pea plant as a model system for his studies EXCEPT ________. A) peas have a relatively short generation time B) peas produce large numbers of seeds C) he could control which parents were involved in mating D) peas only reproduce by cross-fertilization

An unaffected woman for a human disorder marries and unaffected man and they have children. This results in 3 affected sons, and one unaffected daughter, which ends up having children later on with an unaffected man and has 2 affected sons. A) Draw a simple pedigree diagram for this family, including a legend. B) What is the likely mode of inheritance of this trait: Please explain C) Provide the genotypes of the original mother and the daughter. Use a capital letter for the dominant allele and lowercase letter for the recessive allele. D) If one of the affected sons from the original marriage marries a 2nd cousin that is a carrier of this trait and has children, what is the probability that they will have 3 affected sons?

a) 5% b) 45% c) 90% d) 10%

Now assume that the pedigree shown in question 1 shows the inheritance of a rare genetic disease. a) The disease is most likely autosomal dominant b) The disease is most likely autosomal recessive c) The disease is equally likely to be either autosomal dominant or autosomal recessive, but cannot be x-linked d) Cannot be determined from the information given