The length of a dog's tail is an inherited trait. The allele for short tails is dominant (T) over the
allele for long tails (t).
A dog breeder mates two short-tailed dogs (parents). One parent is homozygous and the other is
heterozygous for this trait.
A litter of twelve puppies (first generation), all with short tails, is produced. The breeder mates
one of the twelve puppies (first generation) with a short-tailed dog from another litter. A litter of
ten puppies is produced (second generation). The breeder is surprised when one of the second-
generation puppies has a long tail. HURRY UP!