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Home Q & A Board Biology-Related Homework Help Genetics and Developmental Biology
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Finkas Finkas
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11 years ago
their 9 offspring show the recessive phenotype. What is the genotype of the first parent?

A) AA
B) Aa
C) aa
D) The answer cannot be determined from this information.
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toneytoney
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11 years ago
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#2
11 years ago
B) Aa
because the phenotypic ratio is approximately 1:1

Smiling Face with Halo
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#3
11 years ago
For the second individual to have recessive phenotype, the genotype has to be aa.
And the individual with the dominant phenotype can  be either AA or Aa.

Since 4 of the 9 offspring show recessive phenotype, it means they carry aa genotype.  And these 4 have received "a" from both parents.  It follows then that the both the parents have the ability to pass on "a" to their offspring.

Thus, the first parent has to be Aa
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