Punnett Square

The Punnett Square

          One of the easiest ways to calculate the mathematical probability of inheriting a specific trait was invented by an early 20^th century English geneticist named Reginald Punnett. His technique employs what we now call a Punnett square. This is a simple graphical way of discovering all the potential combinations of genotypes that can occur in children. Punnett squares are standard tools used by genetic counselors. The likelihood of inheriting many traits, including useful ones can be predicted using them.

 

The letters inside the boxes indicate probable genotypes (genetic makeup) of offspring resulting from the cross of particular parents. There are 4 boxes and the genotypic results can be written either as fractions or ratio. 

 

If only one parent has single copy of a dominant allele for a dominant disorder, their children will have 50% chance of inheriting the disorder and 50% of being entirely normal.

Punnett Square

The Punnett Square

          One of the easiest ways to calculate the mathematical probability of inheriting a specific trait was invented by an early 20^th century English geneticist named Reginald Punnett. His technique employs what we now call a Punnett square. This is a simple graphical way of discovering all the potential combinations of genotypes that can occur in children. Punnett squares are standard tools used by genetic counselors. The likelihood of inheriting many traits, including useful ones can be predicted using them.

 

The letters inside the boxes indicate probable genotypes (genetic makeup) of offspring resulting from the cross of particular parents. There are 4 boxes and the genotypic results can be written either as fractions or ratio. 

 

If only one parent has single copy of a dominant allele for a dominant disorder, their children will have 50% chance of inheriting the disorder and 50% of being entirely normal.