Expert: Walter Hintz - 2/9/2010

Question
This is a math question that I am trying to make sure my son and I under is correctly.

Father is homozygous for his tall eyeballs while mother is heterozygous for her tall eyeballs.  Some members of her family has short eyes, which is a recessive trait.  New born baby has short eyeballs.  Did the hospital make a mistake?  

My son's answer was no due to the baby skipped a generation and got the short eyeballs from her family.  His he correct.

Answer
Lets look at the problem
Let H = Tall
h = short eyes
 Father is HH  Tall must dominate since mother is tall
 Mother is Hh
  Any baby from this cross would have tall eyeballs
  Skipping generations only occurs when the trait is sex linked (traits on 23rd pair of chromosomes)