Answer to Question #149979 in Genetics for Josh

Question

Rh factor (D and d) is a factor located on red blood cells (RBC) of humans: specifically, it is a glycolipid on the RBC membrane. Rh+ has the glycolipid while Rh- does not. It displays simple Mendelian inheritance with Rh+ being dominant. Joe has Rh- blood and his wife Sue has Rh+. They have a child who is Rh+. Show this in a Punnet Square.

Answer 1

If the father's phenotype is Rh+ his genotype may be Rh+ (DD) or Rh+ (Dd)

If the mother's phenotype is Rh+ her genotype may be Rh+ (DD) or Rh+ (Dd)

P ♀ Rh+ (DD) x ♂Rh+ (DD)

F1      Rh+ (DD) -100%

P ♀ Rh+ (Dd) x ♂Rh+ (Dd)

F1

75% on phenotype Rh+