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Mendel crossed peas having round seeds and yellow cotyledons (seed leaves) with peas having wrinkled seeds and green cotyledons. All the F1 plants had round seeds with yellow cotyledons. Based on this cross, what is the probability that an organism in the F2 generation will have round seeds and green cotyledons and NOT be true breeding? (Hint: Think carefully about what true breeding means in terms of genotype.)YOU'RE CALCULATING NOT TRUE BREEDING****a. 1/16b. 1/8c. 1/4d. 1/32e. 3/16f. 3/4

Respuesta :

Answer:

e. 3/16

Explanation:

When crossing homozygote dominant genotype(AABB) with homozygote recessive genotype(aabb) as F0, you will get 100% F1 of heterozygote(AaBb). That means round seeds(A) and yellow cotyledons(B) are the dominant traits while wrinkled seed(a) and green cotyledons(b) are the recessive traits.

The question asking for round seeds(A) and green cotyledon(b), one dominant and one recessive trait. The ratio of the trait in F2 crossing should be  

9 (AB) : 3 (Ab) :3 (aB) : 1 (ab)

The probability will be: 3/(9+3+3+1)= 3/16

 

Pure breed or true breeding is a term used for a child that has the same phenotype as its parents. Since all F1 is round seeds and yellow, there should be any true breed that gives round seeds and green. Since all of the child is not true breed, then the answer is 3/16.

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