Intro to Genetic Crosses
Use this key for the following genetic problems
T = tall
t = short
Y = yellow
y = green
S = smooth
s = wrinkled
R = round
r = oval
B = black
H = short hair
C = curly hair
P = pugged nose
b = brown
h = long hair
c = straight hair
p = round nose
A. Genotypes
1. What is an allele?
2. Where can you get one?
3. You have ______ alleles for each trait
4. The combination of alleles is known as a ____________________
5. Write the genotypes for the following:
a. ________ Homozygous tall
b. ________ Heterozygous round
c. ________ Brown
d. ________ Homozygous pugged nose
e. ________Heterozygous short hair
f. ________round nose
g. ________Homozygous curly hair
h. ________Oval
B. Phenotypes
1. What is a phenotype?
2. Write the phenotype for the following (include the terms heterozygous and homozygous
when appropriate)
. _____________________________________________ SSRr
7. _____________________________________________ ppHH
8. _____________________________________________ Ttss
9. _____________________________________________ RrYy
10. _____________________________________________ BBHhcc