Name ________________________
Period_____
Date_________
Dragon Genetics
In dragons, the ability to breathe fire is a
recessive trait (dd). Homozygous dominant
dragons (DD) cannot produce fire or smoke at
all. Heterozygous dragons (Dd) can produce
smoke, but no fire.
1. Cross a fire breathing dragon with a
homozygous dominant dragon. Use a Punnett
square to support your answer. dd x DD
Dd
Dd
What are the resulting genotypes? Give the
percentages. 100% Dd
Dd
Dd
What are the resulting phenotypes? Give the percentages.
100% Smoke producing
2. Cross two smoke-producing only dragons (Dd). Use a Punnett square to support your
answer.
DD
Dd
What percentage of the offspring can produce fire?
Dd
dd
25% (1/4 have dd)
What percentage of the offspring can’t produce fire? 75% (3/4 have DD or Dd)
3. In dragons, the presence of horns (H) is dominant over no horns (h). If a heterozygous
horned dragon mates with a homozygous hornless dragon, what are the offspring’s
genotypes and phenotypes? Hh x hh
What are the resulting genotypes? Give the percentages.
Hh
Hh
hh
hh
50% Hh
50% hh
What are the resulting phenotypes? Give the percentages.
50% Horned
50% Hornless
4. In fire breathing dragons, the color of their fire is an inherited trait. Orange fire (B) is
dominant over blue fire (b). If a dragon with blue fire mates with a homozygous dragon
with orange fire, what percentage of the offspring would breathe orange fire? BB x bb
What percent of the offspring would breathe blue fire?
Bb
Bb
Bb
Bb
0% (none with bb genotype)
What percent of the offspring would breathe orange fire?
100% (all Bb)
5. Wing length in dragons is an inherited trait. Long wings (L) are dominant over short
wings (l). Based on the Punnett Square below, determine the parents’ genotypes and
phenotypes.
LL
Ll
Parent’s Genotypes
Ll x Ll
Ll
ll
Parents’ Phenotypes Both long winged