Four genes A B D and E are responsible for length of pollen

Four genes, A, B, D, and E are responsible for length of pollen (long versus short), plant height (tall versus dwarf), seed color (yellow versus green), and seed texture (smooth versus wrinkled), respectively [dominant traits listed first, recessive traits listed second]. These four genes behave according to Mendel’s principles. Starting with a true-breed pair, a tall plant with long pollen and smooth yellow seeds, and a dwarf plant with short pollen and wrinkled green seeds, answer the following questions.

A. Define the genotypes of the P-generation plants.

B. An F1 generation individual was mated with a true-breed tall plant with long pollen and smooth green seeds. What is the probability they will produce an offspring with the same genotype as the true-breed individual?

C. What is the probability of producing a plant with long pollen and green seeds in the F2 generation?

D. What is the probability of producing a dwarf F2 plant with short pollen and wrinkled yellow seeds?

Solution

Answer:

Long vs short = AA vs aa

Tall vs dwarf = BB vs bb

Yellow vs green = DD vs dd

Smooth vs Wrinkled= EE vs ee

A).

True breeding Tall plant with long pollen and smooth yellow seeds = BBAAEEDD

Dwarf plant with short pollen and wrinkled green seeds = bbaaeedd

B).

BBAAEEDD x bbaaeedd

BbAaEeDd ---F1

F1 x true-breed tall plant with long pollen and smooth green seeds (BBAAEEdd)

BbAaEeDd x BBAAEEdd

Bb x BB = BB (1/2), Bb (1/2)

Aa x AA = AA (1/2), Aa (1/2)

Ee x EE = EE (1/2), Ee (1/2)

Dd x dd = DD(1/2), dd(1/2)

The proportion of True breed individual (BBAAEEdd) is = ½ * ½ * ½ * 1/2 = 1/16

C).

The probability of producing a plant with long pollen and green seeds in the F2 generation

BbAaEeDd x BbAaEeDd (F1 x F1)

F2 = Long pollen and green seeds = A_dd= ¾ * ¼ = 3/16

D).

The probability of producing a dwarf F2 plant with short pollen and wrinkled yellow seeds

Plant with short pollen and wrinkled yellow seeds = aaeeD_ = ¼ * ¼ * ¾ = 3/64