Sample Genetics Problems
1. Brad, who has curly hair, and Sandi, who has straight hair, have a child. If Brad's father had straight hair, what are the odds that Brad and Sandi's child will have curly hair? (C = curly hair, c = straight hair)
2. Nathan and Ashlee both have normal vision, but Ashlee's mother is color blind, while none of Nathan's forebears have ever exhibited color blindness. If Nathan and Ashlee have a child, what are the odds that the child will be color blind? (N = normal vision, n = color blind)
3. Nina's brother is a hemophiliac. What are the odds that she will have a hemophiliac child, given that her husband Martin is not a hemophiliac? (R = regular clotting, r = hemophilia; sex-linked trait)
4. George has brown hair; Emily has red hair. Both of their mothers had blond hair. What are the odds that George and Emily's child will be red-haired? (B = brown hair, r = red hair, b = blond hair; B > r > b, meaning that r is recessive to B but dominant over b.)
5. Charles is double-jointed, though his mother was not. Marie has normally jointed fingers. What can be predicted about their child? (D = double jointed, d = normal joints)
6. Brown-eyed Amelia and green-eyed Ichabod have fallen in love, but before getting married, they want to assess the odds of having a blue-eyed child, since Amelia's mother, very wealthy but very controlling, has promised to disown her if this should occur. Both of Amelia's parents have hazel eyes; Ichabod's mother has blue eyes. Should the couple marry? (B = brown, G = green, b = blue; co-dominant with BG = hazel)
7. Micaiah, a type I diabetic, has married Theophanie, who is not diabetic, though her mother was. What are the odds that their child will develop type I diabetes? (D = normal, d = type I diabetes; sex linked trait).
8. The earth has passed through a radiation cloud, producing a spate of mutations. One of these results in a new set of hair colors: the allele for purple hair (P) is dominant over that for green hair (G), which in turn is dominant over that for orange hair (o). The trait is sex linked. Avigdor, who has purple hair, marries Clarinda, who has green hair, not knowing that Clarinda's mother's hair was a bright shade of orange. What can be predicted about the hair color of their child?
Click here for answer key - but try the problems first, please!