Question

In corn, a colored aleurone is due to the presence of a R allele; r/r is colorless. Another gene controls the color of the plant, with g/g being yellow and G_ being green. A plant of unknown genotype is test-crossed, and the following progeny plants were obtained.

Colored green       89

Colored yellow      13

Colorless green     9

Colorless yellow    92

1. What was the phenotype and genotype of the plant used for the test-cross?
2. What were the phenotypes of the plants used to produce the plant with the unknown genotype? (Assume that the parentals were homozygous.)
3. What is the approximate map distance between the R locus and the G locus?

Answer 1

Answers

a. From the given data most common phenotype of  offspring are colored Green and colorless yellow.
The plant will be R G or r g (with the dominant alleles in cis to each other). Hence finally it is  colored and green.

b. The parentals  responsible for the F1 generation of plant have been colored green (R G) as well as color less yellow (r g).

c. There will be  203 plants in that 22 are recombinant and it also has 9.6 map units apart.

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