Use the following information to answer the questions below.
A plantlike organism on the planet Pandora can have three recessive genetic traits: bluish leaves, due to an allele (a) of gene A; a feathered stem, due to an allele (b) of gene B; and hollow roots due to an allele (c) of gene C. The three genes are linked and recombine as follows:
A geneticist did a testcross with an organism that had been found to be heterozygous for the three recessive traits and she was able to identify progeny of the following phenotypic distribution (+ = wild type):

-What is the greatest benefit of having used a testcross for this experiment?
A) The homozygous recessive parents are obvious to the naked eye.
B) The homozygous parents are the only ones whose crossovers make a difference.
C) Progeny can be scored by their phenotypes alone.
D) All of the progeny will be heterozygous.
E) The homozygous recessive parents will be unable to cross over.

Question

Use the following information to answer the questions below.
A plantlike organism on the planet Pandora can have three recessive genetic traits: bluish leaves, due to an allele (a) of gene A; a feathered stem, due to an allele (b) of gene B; and hollow roots due to an allele (c) of gene C. The three genes are linked and recombine as follows:
A geneticist did a testcross with an organism that had been found to be heterozygous for the three recessive traits and she was able to identify progeny of the following phenotypic distribution (+ = wild type):
 
-What is the greatest benefit of having used a testcross for this experiment?
A) The homozygous recessive parents are obvious to the naked eye. 
B) The homozygous parents are the only ones whose crossovers make a difference. 
C) Progeny can be scored by their phenotypes alone. 
D) All of the progeny will be heterozygous. 
E) The homozygous recessive parents will be unable to cross over.

Quizplus · Accepted Answer

The greatest benefit of using a testcross is that progeny can be scored by their phenotypes alone. This allows for easy identification of the genotype of the organism being tested. In this experiment, the geneticist was able to identify the proportions of different phenotypes in the progeny and deduce the genotype of the heterozygous parent. It is not necessary to identify the homozygous recessive parents or their ability to cross over in order to use a testcross.

Use the Following Information to Answer the Questions Below