Pepper colors range from bright red, orange, and yellow shades, to dark green an
ID: 144663 • Letter: P
Question
Pepper colors range from bright red, orange, and yellow shades, to dark green and brown shades. Coloration in bell peppers is controlled by alleles for two genes: Red (R) is incompletely dominant to yellow (r) and No chlorophyll (G), no green pigment, is dominant to chlorophyll (g), green pigment.
A. You cross a red pepper with a green pepper and all the F1 progeny are orange.
What are the genotypes of the red and green parents?
What is the genotype of the F1’s?
B. What genotypes and phenotypes, in what proportions, do you expect in the F2 progeny of the orange F1 peppers?
Explanation / Answer
Answer: A
Types of alleles are:
Red color allele: R which is incomplete dominant it means when one allele not capable of dominating another allele completely due to which a new phenotype production takes place. For example
RR: will give red bell peppers
rr: will give yellow bell peppers, but due to incomplete dominance
Rr: will not give Red phenotype due to incomplete dominance of red allele and will produce new orange phenotype.
No green pigment: G is dominant over green pigment allele g.
F1 cross between red pepper with green pepper:
F1 cross- RR X gg
Alleles segregation- R, R, g, g
F1 genotypes - Rg: Rg: Rg: Rg
Answer B: when red bell peppers are crossed with yellow peppers in F1 generation orange bell peppers are produced due incomplete dominance of red allele. Let’s see below in cross.
Red pepper genotype: RR
Yellow w pepper genotype: rr
F1 cross: RR X rr
F1 genotype: Rr, Rr, Rr, Rr (all orange)
F2 cross between orange phenotype of F1 generation
F2 cross: Rr X Rr
Allele segregation: R, r, R, r
F2 genotypes: RR : Rr :Rr :rr
Ratio of phenotypes: Red: Orange: Orange: Yellow (1/4 Red, 2/4 Orange, 1/4 Yellow)
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