Marfan syndrome is a condition that affects a protein called fibrillin. Fibrillin helps support many parts of the human body and also affects growth. Humans with Marfan syndrome tend to be taller than average and have long limbs, fingers, and toes. They may also have heart problems and other organ issues. In a group of humans, some individuals have Marfan syndrome and others do not. In this group, the gene for the Marfan syndrome trait has two alleles. The allele for having Marfan syndrome (M) is dominant over the allele for not having Marfan syndrome (m).
Complete the Punnett square below to show all possible genotypes of the offspring from a cross between two humans.