In a dihybrid cross between two heterozygous pea plants ($AaBb \times AaBb$) with independently assorting genes, what proportion of the offspring will display at least one dominant phenotype?
Answer and explanation
Correct answer: A.
- Step 1: A standard dihybrid cross produces a phenotypic ratio of .
- Step 2: Only the double homozygous recessive offspring () fail to display any dominant phenotype, occurring with probability .
- Step 3: The complementary probability of displaying at least one dominant phenotype is .
Answer
15/16.
Why not the others: '' is the proportion displaying both dominant phenotypes; '' is the proportion displaying one specific dominant and one recessive phenotype; '' is double recessive.
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