2. For each of the genotypes below, determine the phenotype.
Purple flowers are dominant to white.
PP ___________________________
Pp ___________________________
pp ___________________________
Round seeds are dominant to wrinkled.
RR ___________________________
Rr ___________________________
rr ___________________________
Bobtails are recessive (long tails dominant).
TT ___________________________
Tt ___________________________
tt ___________________________
3. For each phenotype, list the genotypes. (Remember to use the letter of the dominant trait)
| Straight hair is dominant to curly. ____________ straight ____________ straight ____________ curly | Tail spikes are dominant to plain tails. ____________ pointed ____________ pointed ____________ 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)
What percentage of the offspring will be round? _______
What percentage of the offspring will be round? _______
What percentage of the offspring will be round? ___________
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 Tt plant is crossed with a Tt plant.
What percentage of the offspring will be short? ______
7. A heterozygous round seeded plant (Rr) is crossed with a homozygous round seeded plant (RR).
What percentage of the offspring will be homozygous (RR)? ____________
8. A homozygous round seeded plant is crossed with a homozygous wrinkled seeded plant.
What are the genotypes of the parents? __________ x __________
What percentage of the offspring will also be homozygous? _______ What is the genotype of all of the offspring? ______
9. In pea plants purple flowers are dominant to white flowers.
If two white flowered plants are cross, what percentage of their offspring will be white flowered? ______
10. A white flowered plant is crossed with a plant that is heterozygous for the trait.
What percentage of the offspring will have purple flowers? _____________
11. Two plants, both heterozygous for the gene that controls flower color are crossed.
What percentage of their offspring will have purple flowers? ______________
What percentage will have white flowers? ___________
12. In guinea pigs, the allele for short hair is dominant.
What genotype would a heterozygous short haired guinea pig have? _______
What genotype would a purebreeding short haired guinea pig have? _______
What genotype would a long haired guinea pig have? ________
Show the cross for two heterozygous guinea pigs.
What percentage of the offspring will have short hair? ________
What percentage of the offspring will have long hair? _______
Peas, Please – practice setting up squares for basic Mendelian traits in pea plants (Key, TpT)
Practice Punnett Squares with Skinny Pigs – hairless guinea pigs are the result of a recessive gene (Key, TpT)
Fruit Fly Genetics (Vg) – practice worksheet on vestigial wing flies (recessive trait)
Explore the Genetics of Corn Snakes – dihybrid crosses with corn snakes, color is polygenic
