Assume that Mendel selfed a bushy pea plants that was grown

Assume that Mendel selfed a bushy pea plants that was grown from yellow seed (an F1 hybrid). This hybrid had one parent that was spindly and grown from a green seed; these were the wildtype phenotypes and that parent was true-breeding. He then collected 400 seed from the self of the bushy pea plant and recorded the seed color as well as the bushyness of the plant that grew from that seed.

A) Given the standard notation rules for naming genes that we discussed in class what would be the most logical name for the two genes being investigated in this cross?

B) For each gene, is the mutation dominant or recessive? Explain your reasoning.

C) What ratio of yellow to green seed color would you expect among the 400 F2 offspring? Explain your reasoning using genetic notation (show genotype of parent and progeny).

D) Assuming that the two genes show independent assortment, how many of the green peas would you also expect to grow into spindly pea plants?

Thank you!

Solution

yellow seed phenotype as dominant trait-----------------Y allele

green seed as recessive trait-------------------y    allele

bushy trait-------------------B

spindly----------------b

bushy pea plant –(yellow )          YY   X    green s        yy (spindly)

F1 hydrid--------------BbYy---------bushy pea plant & yellow

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F1 hydrid--------------BbYy---------bushy pea plant

F1 hydrid--------------BbYy--------- x     F1 hydrid--------------BbYy

BY

By

bY

by

BY

By

bY

by

Phenotypic ration :9:3:3:1

9/16

Bushy yellow

9/16 x 400

225

3/16

Bushy green

3/16 x 400

75

3/16

spindly yellow

3/16 x 400

75

1/16

Spindly green

1/16 x 400

25

total

400

C) What ratio of yellow to green seed color would you expect among the 400 F2 offspring? Explain your reasoning using genetic notation (show genotype of parent and progeny).

yellow to green seed color =225+75 /75+25=3:1

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D) Assuming that the two genes show independent assortment, how many of the green peas would you also expect to grow into spindly pea plants?

Answer =25