Simple Genetics
1. For each genotype, indicate whether it is heterozygous (HE) or homozygous (HO)
AA ______
Ee __________
Ii _________
Mm ________
Bb ______
ff ___________
Jj ________
nn ___________
Cc _______
GG _______
kk ________
OO __________
Dd ______
HH _________
Ll _________
2. For each of the genotypes below, write the phenotype.
Purple flowers are dominant to white flowers
Round seeds are dominant to wrinkled
PP ___________________________
RR ___________________________
Pp ___________________________
Rr ___________________________
pp ___________________________
rr ___________________________
Brown eyes are dominant to blue eyes
Bobtails are recessive (long tails dominant)
BB ___________________________
TT ___________________________
Bb ___________________________
Tt ___________________________
bb ___________________________
tt ___________________________
3. For each phenotype, write the genotype. (Remember to use the letter of the dominant trait)
Straight hair is dominant to curly.
Pointed heads are dominant to round heads.
____________ straight
____________ pointed
____________ straight
____________ pointed
____________ curly
____________ round
4. Set up the square for each of the crosses listed below. The trait being studied is round seeds (dominant)
and wrinkled seeds (recessive).
Practice with Crosses. Show all work!
5. A TT (tall) plant is crossed with a tt (short plant). What percentage of the offspring will be tall?
6. A heterozygous plant (Tt) is crossed with another heterozygous (Tt) plant. What percentage of the
offspring will be short?
7. A purebred tall plant is crossed with a hybrid plant. What percentage of the offspring will be short? What
percent will be tall?