Biology 1201A Lecture Notes - Dewoitine D.9
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In rats, several independently assorting autosomal genes affectcoat color. Gene A controls the distribution of yellow pigment inhair, and gene B causes black pigmentation. The two genes interactas follows: AâBâ (gray), Aâbb (yellow), aaBâ (black), and aabb(cream). These genotypes are only expressed in the presence of thedominant allele of a third gene, C; rats with genotype cc arealbino.
a. Deduce the genotype of each albino mice, to the extent thatis possible, in the following table. Explain your answers.
True-breeding parents | F1 | F2 offspring |
Gray x albino-1 | All gray | 3/4 gray : 1/4 albino |
Gray x albino-2 | All gray | 9/16 gray : 3/16 yellow : 4/16 albino |
b. Deduce the genotype and phenotype of each parent in thefollowing table. Explain your answers.
Parents | Numbers of offspring |
Cross 1 | 135 gray, 83 albino, 47 yellow, 44 black, 16 cream |
Cross 2 | 103 albino, 74 black, 25 cream |
c. A gray-colored rat is mated with one that is yellow. Theoffspring include an albino rat and a cream-colored rat. Diagramthis cross. Be sure to include the Punnett square and thephenotypic ratio in the offspring.
In rats, several independently assorting autosomal genes affectcoat color. Gene A controls the distribution of yellowpigment in hair, and gene B causes black pigmentation. Thetwo genes interact as follows: AâBâ (gray), Aâbb(yellow), aaBâ (black), and aabb (cream). Thesegenotypes are only expressed in the presence of the dominant alleleof a third gene, C; rats with genotype cc arealbino.
a. Deduce the genotype of each albino mice, to the extent that ispossible, in the following table. Explain your answers.
True-breeding parents | F1 | F2 offspring |
Gray x albino-1 | All gray | 3/4 gray : 1/4 albino |
Gray x albino-2 | All gray | 9/16 gray : 3/16 yellow : 4/16 albino |
Part a. |
Genotype of albino-1 parent is ⦠Explanation: |
Genotype of albino-2 parent is ⦠Explanation: |
b. Deduce the genotype and phenotype of each parent in the followingtable. Explain your answers.
Parents | Numbers of offspring |
Cross 1 | 135 gray, 83 albino, 47 yellow, 44 black, 16 cream |
Cross 2 | 103 albino, 74 black, 25 cream |
Part b. | Parental phenotypes | Parental genotypes |
Cross 1 | x | x |
Explanation: |
Part b. | Parental phenotypes | Parental genotypes |
Cross 2 | x | x |
Explanation: |
c. A gray-colored rat ismated with one that is yellow. The offspring include an albino ratand a cream-colored rat. Diagram this cross. Be sure to include thePunnett square and the phenotypic ratio in the offspring.
Part c. |
Cross is ⦠x Explanation: |
Punnett Square
Fill the punnet sq | ||||
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