Guida passo passo – Opzioni esotiche perché non c`è niente di più

Guida passo passo – Opzioni esotiche perché non c`è niente di più

Name: ____________________________
Date: _____________________
Period: ______
HOMEWORK: PUNNETT SQUARES - DIHYBRID CROSSES
For each dihybrid cross shown below, fill in the Punnett squares correctly.
Rrbb × rrBb
GgEe × GgEE
TTpp × TtPp
Determine the product of each pair of percentages or fractions.
1. 25% × 25% = ___________
4. ½ × ¾ = ___________
2. ¼ × ¼ = ___________
5. 25% × 0% = ___________
3. 75% × 50% = ___________
6. 50% × 50% = ___________
Complete the dihybrid crosses shown below and answer each question. Be sure to create your
Punnett squares and show you math for each question.
1. In flies, red eyes (R) are dominant to brown eyes (r) and brown bodies (B) are dominant to yellow
bodies (b). A fly with genotype RrBb is mated with a fly with genotype rrbb. What fraction of offspring
will have red eyes and brown bodies?
2. In pea plants, smooth peas (S) are dominant to wrinkled peas (s) and purple flowers (P) are dominant
to white flowers (p). Two plants that are heterozygous for both traits (SsPp) are crossed. How many
different genotypes will appear in the offspring?
3. In certain birds, yellow feathers (g) are recessive to green feathers (G) and short beaks (l) are
recessive to long beaks (L). A bird with genotype ggLl is crossed with a bird with genotype GgLl. What
percentage of offspring are expected to have yellow feathers and long beaks?
4. In a certain species of mammals, gray fur (G) is dominant to white fur (g) and brown eyes (B) are
dominant to blue eyes (b). An animal with white fur and blue eyes is crossed with an animal that has
gray fur and brown eyes (GGBb). What trait will appear in all of the offspring of this mating?
5. In cats, long hair (H) is dominant to short hair (h), and long tails (T) are dominant to short tails (t).
Two cats that are heterozygous for both traits (HhTt) produce a litter of kittens. What percentage of
offspring will be homozygous recessive for both traits?
6. In plants, being tall (T) is dominant to being short (t), and smooth peas (S) are dominant to wrinkled
peas (s). A tall plant with smooth peas (TtSs) is crossed with a short plant with wrinkled peas. What
percentage of offspring will be tall with wrinkled peas?
7. In certain birds, green feathers (G) are dominant to yellow feathers (g), and long beaks (L) are
dominant to short beaks (l). Two birds that are heterozygous for both traits (GgLl) produce offspring.
What percentage of offspring will have genotype GGLL?
8. In flies, red eyes (R) are dominant to brown eyes (r) and brown bodies (B) are dominant to yellow
bodies (b). A fly with genotype (RRbb) is mated with a fly that is (rrBb). What fraction of the offspring
will have red eyes and yellow bodies?