Punnett Squares for Autosomal Recessive Conditions
Punnett Squares for Autosomal Recessive Conditions
Description:
Below are sample Punnett squares for autosomal recessive conditions. The disease-causing mutation is denoted by the lower case letter a. The normal gene is denoted by the capital letter A . 
The Punnett square to the left is representative of possible reproductive outcomes should a female who is a carrier for an autosomal recessive mutation have children with a male who is also a carrier for the same condition. Both the woman and the man are heterozygotes.
This couple has a 25% chance with each pregnancy of having a child without a mutation, a 50% chance of having a child who is an unaffected carrier (a heterozygote), and a 25% chance of having child who inherits 2 copies of the mutation (clinically affected).
The Punnett square to the left is representative of possible reproductive outcomes should a female who is a carrier for an autosomal recessive mutation have children with a male who is neither clinically affected nor a carrier of the condition.
This couple has a 50% chance with each pregnancy of having a child who inherits 1 copy of the mutation (a carrier) and a 50% chance of having a child who has no copies of the mutation (clinically unaffected).
The Punnett square to the left is representative of possible reproductive outcomes should a female with an autosomal recessive disease have children with a male who does not have a mutation for the autosomal recessive condition.
This couple is expected to only have children who inherit 1 copy of the mutation (carriers).
The Punnett square to the left is representative of possible reproductive outcomes should a female with an autosomal recessive disease have children with a male who is a carrier for the same condition.
This couple has a 50% chance with each pregnancy of having a child who inherits 1 copy of the mutation (a carrier) and a 50% chance of having a child who inherits 2 copies of the mutation (clinically affected).
