Direction: Read each Dihybrid situation very carefully. In each of the items, show the genetic cross thru a PUNNETT SQUARE and ANSWER the follow-up questions.
A. A pea plant is heterozygous for both pod shape (inflated) and pod color (green) was crossed. Make an interpretation of this genetic cross, thru the following analysis:
1. Identify the Parental Allele.
2. Show the completed PUNNETT SQUARE with Phenotypes and Genotypes.
3. How many Offspring are counted in the Punnett Square?
4. How many Kinds of Phenotypes are there? Enumerate them.
5. Give the Phenotypic Ratio based on the list in letter d.
6. How many Kinds of Genotype appeared in the Punnett Square? List them according to the order of
appearance in the Punnett Square.
7. Give the Genotypic Ratio based on letter f.
8. In a filial generation of 64 pea plants, how many will be:
a. Of the same allele as their parents?
b. Inflated and green?
c. Recessive?
d. Of dominant character?
e. Pure breeding?
f. Hybrid for pod shape but Pure breed for pod color?
g. Dominant for pod shape but Recessive for pod color?
9. What is the Percentage of each group of organisms in number 8? Answer must be in accordance with the letters in question number eight.
A. A pea plant is heterozygous for both pod shape (inflated) and pod color (green) was crossed. Make an interpretation of this genetic cross, thru the following analysis:
1. Identify the Parental Allele.
2. Show the completed PUNNETT SQUARE with Phenotypes and Genotypes.
3. How many Offspring are counted in the Punnett Square?
4. How many Kinds of Phenotypes are there? Enumerate them.
5. Give the Phenotypic Ratio based on the list in letter d.
6. How many Kinds of Genotype appeared in the Punnett Square? List them according to the order of
appearance in the Punnett Square.
7. Give the Genotypic Ratio based on letter f.
8. In a filial generation of 64 pea plants, how many will be:
a. Of the same allele as their parents?
b. Inflated and green?
c. Recessive?
d. Of dominant character?
e. Pure breeding?
f. Hybrid for pod shape but Pure breed for pod color?
g. Dominant for pod shape but Recessive for pod color?
9. What is the Percentage of each group of organisms in number 8? Answer must be in accordance with the letters in question number eight.
Answers & Comments
Explanation:
1. Parental Alleles: IiGg x IiGg
2. Punnett Square:
| | I | i |
|---|---|---|
| G | IG | iG |
| g | Ig | ig |
3. There are 16 offspring in the Punnett Square.
4. There are two kinds of phenotypes: inflated and green, and constricted and yellow.
5. The phenotypic ratio is 9:3:3:1 (9 inflated and green, 3 inflated and yellow, 3 constricted and green, 1 constricted and yellow).
6. There are three kinds of genotype: IIGG, IiGG, and IiGg.
7. The genotypic ratio is 1:2:1 (1 IIGG, 2 IiGG, 1 IiGg).
8.
a. 32 will be of the same allele as their parents.
b. 9 will be inflated and green.
c. 16 will be recessive.
d. 48 will be of dominant character.
e. 16 will be pure breeding.
f. 16 will be hybrid for pod shape but pure breed for pod color.
g. None will be dominant for pod shape but recessive for pod color.
9.
a. 50%
b. 14.06%
c. 25%
d. 75%
e. 25%
f. 25%
g. 0%