Allele

Use the same letter for both alleles: a capital for the dominant allele and a lower-case letter for the recessive allele.

Put one allele from each parent in every offspring box. Gametes carry one allele for the gene, not a pair.

State that cystic fibrosis is a disorder of cell membranes caused by a recessive allele, whereas polydactyly means extra fingers or toes and is caused by a dominant allele.