Weird Genetics Problems

Solve the following problems showing the genetic cross, Punnett square, and answer any questions. Use the "dash" technique where appropriate.

  1. A male and female chimpanzee are taunting each other by making faces and sticking their tongues out (sort of like high school students). One of them is a heterozygous tongue-roller and the other is a non-roller. Well nature takes it's course and the chimpanzees fall in love and have babies. Write the phenotype and the genotype ratios for the babies. (R = roller, r = non-roller)


  2. In humans, free earlobes are caused by the dominant allele, E, and attached earlobes by the recessive allele, e. The widow's peak hairline is caused by the dominant allele, H, while the straight hairline is caused by the recessive allele, h. What is the probability that a child from the mating of EeHh x EeHh parents will have a widow's peak and free earlobes?


  3. A lawyer sets out to prove that a child with type A blood is the son of a man with type B blood and a mother with type AB blood. Determine if it is possible for the man to be the father. Is he definitely the father? Explain.


  4. During the fetal pig dissection, Klumzy Kimmel attempts to demonstrate the proper way to use a scalpel and ends up cutting himself. Assuming Klumzy Kimmel has type A blood and all the appropriate equipment is available (and that you want to save him!), what blood types can be given to him? Explain using reference to RBC glycoproteins (antigens) and antibodies.


  5. A green-skinned alien from one quadrant of the universe and a red-skinned alien from another quadrant of the universe have 4 beautiful alien babies in an intergalactic example of incomplete dominance. Miraculously, the babies all have blue skin (a blending of green and red). If green skin is caused by GG and red skin is caused by RR, show how the alien miracle babies were produced (genetically!).


  6. A research lab requires a supply of pure breeding freckled frogs (FF) for a cloning experiment. A lab assistant has a pet frog with freckles but it's uncertain if it is homozygous or heterozygous. A test-cross is called for! The pet frog is crossed with a homozygous recessive smooth (non-freckled) frog (ff). Half of the offspring are freckled frogs and half are smooth. What does this tell you?