Question

For aaBb? What are the 6. In the cross AaBb X aaBb, what are the gametes for AaBb? genotypic (not phenotypic) results for this cross? 7. What is the genotype of a white-eyed male fruit fly? 8. Suppose you count 40 green tobacco seedlings and 2 white tobacco seedlings in one agar plate. Do your results show that both parent plants were heterozygous for the color allele? Explain your answer. 9. Suppose you count tobacco seedlings in six agar plates, and your data are as follows: 125 green plants and 39 white plants. What is the phenotypic ratio? 10. Suppose that students in the laboratory periods before you removed some of the purple and yellow corn kernels on the ears of corn as they were performing the Experimental Procedure. What specific effects would this have on your results?

Answer 1

6) The gametes for AaBb will be AB, Ab, aB & ab. The gametes for aaBb will be aB & ab.

The cross between AaBb & aaBb is shown in below Punnett square.

Gametes	aB	ab
AB	AaBB	AaBb
Ab	AaBb	Aabb
aB	aaBB	aaBb
ab	aaBb	aabb

From the above Punnett square, we find that genotypic ratio will be 1:2:1:1:2:1 for AaBB: AaBb: Aabb: aaBB: aaBb: aabb.

7) Eye color in fruit fly is X-linked trait. White eye is recessive to dominant red eye color.

Let, XR = normal chromosome (Produce wild type red color), Xr = X chromosome containing white allele

So, genotype of white-eyed male fruit fly will be XrY.

8) Yes, both parents are heterozygous for color allele. White seedling is an autosomal recessive condition. In order have white seedlings both parents at least need to be carrier to produce white seedlings.

9) The phenotypic ratio will be 125:39, which is close to the ideal 3:1 ratio in monohybrid cross.

Note: To answer question 10, experimental procedure or aim of that particular experiment require.