Molly the Labradoodle has surprised you with a litter of puppies! Students will use gel electrophoresis to examine the link between genotype and phenotype in Molly’s puppies. By tracking the inheritance of a single trait, students can determine the puppies’ father. This lab allows you to cover Mendelian genetics and the relationship between genotype and phenotype using an engaging and adorable case study. An extension activity allows students to practice tracking the inheritance of multiple genes that affect dog coats.