Name _____________________________Date _______________ Period ________
Genetics Practice Problems #2 - Writing Alleles
Directions: Using the data in Table 1, write the genotype that corresponds to the phenotype
descriptions
Table 1: Mendel's Traits and Symbols for Pea Plants
Traits
Dominant Allele
Symbol
Recessive Allele
Seed Shape
Round
R
Wrinkled
Seed Color
Yellow
Y
Green
Seed Coat Color
Colored
C
White
Pod Shape
Smooth
S
Constricted
Pod Color
Green
G
Yellow
Stem Height
Tall
T
Short
Flower Position
Axial
A
Terminal
Symbol
r
y
c
s
g
t
a
Phenotype
Genotype
1. Heterozygous for height
Tt
2. Homozygous dominant for seed shape
RR
17. Short height
tt
3. Heterozygous colored seed coat
Cc
18. Green seed color
yy
4. Homozygous green pod
GG
19. Terminal flowers
aa
5. Homozygous short
tt
20. Pure wrinkled
rr
6. Homozygous tall
TT
21. Hybrid tall
Tt
7. Homozygous axial
AA
22. Pure round
RR
23. Yellow seed pod
gg
8. Homozygous termina
Tt
aa
Phenotype
16. Constricted pod
Genotype
ss
9. Heterozygous flower position
Aa
24. Hybrid smooth
Ss
10. Heterozygous seed color
Yy
25. Pure smooth pod
SS
11. Homozygous smooth pod
SS
26. Hybrid pod color
Gg
12. Homozygous constricted pod
ss
27. White seed coat
cc
13. Homozygous recessive for seed coat color
cc
28. Wrinkled seed
rr
14. Heterozygous for pod color
Gg
29. Pure colored seed coat
CC
15. Homozygous round seed
RR
30. Hybrid flower position
Aa