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Question: You are trying to breed and commercialize a new strain of the corn by combining several traits th...

You are trying to breed and commercialize a new strain of the corn by combining several traits that your marketing team tells you consumers will like (Yellow kernels, Vitamin-rich, Protein-rich and Sweet). You know alleles of four genes as follows:

Yellow kernels, White kernels (“B gene”, allele dominance unknown)

Vitamin-rich, Vitamin-poor (“N gene”, allele dominance unknown)

Protein-rich, Protein-poor (“R gene” allele dominance unknown)

Sweet, Bland (“T gene”, allele dominance unknown)

You breed together a true-breeding Yellow kernel, vitamin-poor, protein-poor, sweet strain with a true-breeding white kernel, vitamin-rich, protein-rich, bland strain. The F1s all are Yellow kernels, vitamin-rich, protein-poor and bland. You self-cross the F1 lines to obtain F2 plants.

1. What fraction of the F2 generation will be Yellow kernels, vitamin-rich, protein-rich, sweet corn (show your work)?

2. Of the Yellow kernel, vitamin-rich, protein-rich, sweet corn individuals you identify within the F2 population, how many would you have to test to be 95% sure you have found at least one true breeding individual with those same characteristics (show your work)?

Answer 1

Answer. There are four gene play role in the corn content and texture.

As from data it is indicated that yellow is dominant over white and vitamin rich , protein poor and bald are dominant. (According to mendels first law)

1) As there are four gene so total outcomes will be 4⁴ = 256

So probability of having yellow will be 3/4 in F2 generation, vitamin rich = 3/4, protein rich = 3/4 and sweet = 1/4

So in total (3/4)²× (1/4)²= 9/256.

Hence fraction of the F2 generation will be Yellow kernels, vitamin-rich, protein-rich, sweet corn is 9/256.

2) probability of having true breed Yellow kernels, Vitamin-rich, Protein-rich and Sweet can be calculate by genotype frequency.

Genotype frequency for BB = 1/4, NN= 1/4 rr= 1/4 and tt = 1/4 then in total 1/256 corn will be true breed for all this trait.