Crosses Between Two Ducks with Spread-Out Tail Phenotype Always Produce

question 34

Multiple Choice

Crosses between two ducks with spread-out tail phenotype always produce ducklings with spread-out,normal,and pointy tails in a 2:1:1 ratio.In addition,normal-tailed ducks crossed to short-tailed ducks always produce only normal-tailed individuals,while crosses between pointy-tailed and short-tailed individuals always produce only pointy-tailed ducklings.If the tail shape phenotype is controlled by a single locus,what is the expected phenotypic ratio in the progeny of the cross spread-out tail × short tail?

• A)1:0 of spread-out : short
• B)1:1 of normal : pointy
• C)1:1 of spread-out : short
• D)1:1:1:1 of spread-out : normal : pointy : short
• E)3:1 of spread-out : short

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