Question

For the following: 1) Identify the genotypes of the parents 2) Complete a Punnett Square & 3) Give the genotypic AND phenotypic results of the cross (percentage OR ratio)

Problem:

In certain flowers, blue and yellow flowers are incompletely dominant to each other.

Show the cross between a pure blue flower and a pure yellow flower.

Additionally, Using the same flowers cross a green flower with a yellow flower.

(Please write or type response, do not use cursive writing due to visual impairment)

Thank you.

Answer 1

Ans: Incomplete dominance physically shows the blending of both the characters. that means dominant allele is not able to mask the effect of recessive allele.

In given question If Blue is the dominant allele and Yellow is the recessive allele then their genotypes will be:

Blue(BB)  

Yellow (bb)

So, F1 would be BBXbb

	B	B
b	Bb	Bb
b	Bb	Bb

So, all the flowers will be of green color in F1 generation but when F1 generation cross pollinate then

BbXBb

	B	b
B	BB	Bb
b	Bb	bb

genotypic ratio will be 1:2:1 i.e. 1-BB, 2-Bb, 1-bb

Phenotypic ratio will 1:2:1 i.e. 1-Blue, 1-Yellow, 2 green

2) 2nd Case when we cross Green(Bb) flower to yellow Flower (bb)

	B	b
b	Bb	bb
b	Bb	bb

Both phenotypic and genotypic ratio will be 1:1