Two true-breeding stocks of pea plants are crossed. one parent has red, axial flowers and theother has white, terminal flowers; all f1 individuals have red, axial flowers. the genes for flowercolor and location assort independently. if 1,000 f2 offspring resulted from the cross, approximately how many of them would you expect to have red, terminal flowers? a) 65b) 190c) 250d) 565e) 750

Question

Zoey Meza

Biology

14 July, 06:57

Two true-breeding stocks of pea plants are crossed. one parent has red, axial flowers and theother has white, terminal flowers; all f1 individuals have red, axial flowers. the genes for flowercolor and location assort independently. if 1,000 f2 offspring resulted from the cross, approximately how many of them would you expect to have red, terminal flowers? a) 65b) 190c) 250d) 565e) 750

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Byron · Answer 1

This is a typical case of a dihybrid cross.

From the phenotype of the offspring, we can conclude that the gene for the red color of the flower and the gene for the axial position of the flower are dominant.

Since we know that the ratio of phenotypes in a dihybrid cross of independently inherited alleles is

9 (dominant for both traits)

3 (dominant for one trait, recessive for the other)

3 (dominant for the second trait, recessive for the other)

1 (recessive for both traits)

we can expect 3/16 of the f2 generation to be dominamt for one trait and recessive for the other (red, terminal flowers), or to be precise 190 individuals.