Bio 107 HoMEWORK: CLASSICAL GENETICS (10 POINTS) Name: Instructor: 1) A heterozy
ID: 3166798 • Letter: B
Question
Bio 107 HoMEWORK: CLASSICAL GENETICS (10 POINTS) Name: Instructor: 1) A heterozygous gray rabbit is crossed with a homozygous dominant gray rabbit (B gray b- white). a) What is the phenotypic ratio of offspring from this cross? (1.0 Point) b) What is the genotypic ratio of offspring from this cross? (1.0 Point) 2) A breeding experiment was done with wheat beginning with a dark red-kerneled variety and a white-kerneled variety. When plants with these two extreme phenotypes were crossed, all the Fi plants produced light red kernels that were intermediate between the parents. What type of inheritance does this suggest? (1Point) a. polygenic b. incomplete dominance c. codominance d. X-linkage e. Y-linkage 3) The color alleles for the flowers of snapdragons exhibit incomplete dominance. The red color allele is denoted by R and white color allele is denoted r. A pure red snapdragon is crossed with a pure white snapdragon. c) What is the phenotypic ratio of offspring from this cross? (1.0 Point) d) What is the genotypic ratio of offspring from this cross? (1.0 Point)Explanation / Answer
1. Bb x BB
Punnett square analysis:
a. Since all rabbits are gray in color, so the phenotypic ratio is - 4:0
b. The genotypic ratio is - BB:Bb:bb = 2:2:0
2. The answer is: b. Incomplete dominance
One of the traits among dark red kernel and white kernel is dominant. Since after the cross, none of the offspring plants showed parental trait, this means that the effect of the dominant allele is not able to completely mask the effect of the recessive allele. Such a type of inheritance is called incomplete dominance.
3. RR x rr
Punnett square analysis:
c. Phenotypic ratio - 4:0
d. Genotypic ratio - Rr:RR:rr = 4:0:0
B b B BB (Gray) Bb (Gray) B BB (Gray) Bb (Gray)Related Questions
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