Question

A normal appearing couple is found to be heterozygous recessive for albinism. Both have the genotype Aa. The gene responsible for albinism is recessive to the normal pigment-producing gene. What are the chances of their children being albino?
A: 3:4 children will be albino.
B: All children will be albino.
C: 1:4 children will be albino.

Answer 1

Using the Pennett Square to chart the possibility of an offspring showing the recessive albino trait, the odds are 1:4 if both parents carry the genotype Aa. Draw a square and divide into 4 sections. For the father, on top of the first square on the upper left place a "A". on the upper right place a "a". For the mother, down the left side for the top square place an "A" and the lower square an "a". Inside each corresponding square line up the letters to find the genetic traits . In this example , one should get one child "AA" no recessive gene, two offspring with "Aa", carry the recessive gene, and a fourth. "aa" carries and shows trait of recessive gene. thus chances are 1:4 will have the albinism.