You recently discovered a new variety of sweetpea plants in the area surrounding Chernobyl that cannot be crossedwith the sweet pea plants used in Mendel's experiments. Youidentify several pure breeding strains with characteristics thatare similar to those described by Mendel. You found that round (R)was dominant over wrinkled (r) for pea shape and yellow (Y) wasdominant over green (y) for pea colour in monohybridcrosses.
(a) show the expected outcome of a dihybridcross starting with pure breeding plants with round yellow peas andpure-breeding wrinkled green peas. Include all phenotypes and thecorresponding genotypes for parental, F1 and F2 generations. Alsoinclude the expected phenotypic ratios for the F2 generation.Surprisingly, when you performed this cross, you notice someinteresting differences from Mendel's experiments. Although all F1progeny had round yellow peas, the F1 self cross resulted in farfewer round green and wrinkled yellow peas than expected. Beingvery clever, you hypothesize that these loci may be linked in thisvariety of pea and you performed a testcross between F1 plants anddouble homozygous plants with wrinkled green peas. You obtained thefollowing progeny: 445 Round yellow, 48 round green, 52 wrinkledyellow and 455 wrinkled green. (b) Identify the parental andrecombinant classes from the test cross (2 marks). (c) Estimate therecombination frequency using these data, and show your work. (d)Indicate the distance between loci in map units, and show yourwork. (e) Using the recombination frequency you calculated in (c),predict the phenotypic ratio in the F2 generation in the dihybridcross in (a)
You recently discovered a new variety of sweetpea plants in the area surrounding Chernobyl that cannot be crossedwith the sweet pea plants used in Mendel's experiments. Youidentify several pure breeding strains with characteristics thatare similar to those described by Mendel. You found that round (R)was dominant over wrinkled (r) for pea shape and yellow (Y) wasdominant over green (y) for pea colour in monohybridcrosses.
(a) show the expected outcome of a dihybridcross starting with pure breeding plants with round yellow peas andpure-breeding wrinkled green peas. Include all phenotypes and thecorresponding genotypes for parental, F1 and F2 generations. Alsoinclude the expected phenotypic ratios for the F2 generation.Surprisingly, when you performed this cross, you notice someinteresting differences from Mendel's experiments. Although all F1progeny had round yellow peas, the F1 self cross resulted in farfewer round green and wrinkled yellow peas than expected. Beingvery clever, you hypothesize that these loci may be linked in thisvariety of pea and you performed a testcross between F1 plants anddouble homozygous plants with wrinkled green peas. You obtained thefollowing progeny: 445 Round yellow, 48 round green, 52 wrinkledyellow and 455 wrinkled green. (b) Identify the parental andrecombinant classes from the test cross (2 marks). (c) Estimate therecombination frequency using these data, and show your work. (d)Indicate the distance between loci in map units, and show yourwork. (e) Using the recombination frequency you calculated in (c),predict the phenotypic ratio in the F2 generation in the dihybridcross in (a)
