How Do You Make A Punnett Square?
In order to create a Punnett square, you need to know the genotype of each parent. Done correctly, this will produce a chart of the possible genetic makeup of their child. • Draw a box and divide it into four smaller squares. • The mother has both the dominant B gene and the recessive b. The father has two recessive genes. Write the mothher’s genotype along the top and the father’s genotype along the left side. A useful convention in genetics is to use a capital letter for a dominant gene and a lower case letter for the corresponding recessive gene. • Half of their children will have Bb and half will have bb. Fill in the four boxes by combining the genes from the corresponding row and column. It is customary to always write the capital letter first if both dominant and recessive genes are present (so write Bb, not bB.) Each of the four boxes has equal probability of appearing in their offspring. Therefore each possibility represents a 25% chance.
