Question: Assume you recently found a new variety of sweet pea plants in the area surrounding Chernobyl that cannot be crossed with the sweet pea plants used in Mendel’s experiments. You identify several pure breeding strains with characteristics that are similar to those described by Mendel. You found that round (R) was dominant over wrinkled (r) for pea shape and yellow (Y) was dominant over green (y) for pea colour in monohybrid crosses.

(a) show the expected outcome of a dihybrid cross starting with pure breeding plants with round yellow peas and pure-breeding wrinkled green peas. Include all phenotypes and the corresponding genotypes for parental, F1 and F2 generations. Also include the expected phenotypic ratios for the F2 generation. Surprisingly, when you performed this cross, you notice some interesting differences from Mendel’s experiments. Although all F1 progeny had round yellow peas, the F1 self cross resulted in far fewer round green and wrinkled yellow peas than expected. Being very clever, you hypothesize that these loci may be linked in this variety of pea and you performed a testcross between F1 plants and double homozygous plants with wrinkled green peas. You obtained the following progeny: 445 Round yellow, 48 round green, 52 wrinkled yellow and 455 wrinkled green. (b) Identify the parental and recombinant classes from the test cross (2 marks). (c) Estimate the recombination frequency using these data, and show your work. (d) Indicate the distance between loci in map units, and show your work. (e) Using the recombination frequency you calculated in (c), predict the phenotypic ratio in the F2 generation in the dihybrid cross in (a)