Please use the following information to answer the question(s) 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.
A geneticist did a testcross with an organism that had been found to be heterozygous for the three recessive traits and was able to identify progeny of the phenotypic distribution (+ = wild type) shown in Figure 12.3. Figure 12.3
-If recombination frequency is equal to distance in map units, what is the approximate distance between genes A and B?
A) 1.5 map units
B) 3 map units
C) 6 map units
D) 15 map units
E) 30 map units

Question

Please use the following information to answer the question(s) 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.
A geneticist did a testcross with an organism that had been found to be heterozygous for the three recessive traits and was able to identify progeny of the phenotypic distribution (+ = wild type) shown in Figure 12.3.  Figure 12.3
-If recombination frequency is equal to distance in map units, what is the approximate distance between genes A and B?
A) 1.5 map units 
B) 3 map units 
C) 6 map units 
D) 15 map units 
E) 30 map units

Quizplus · Accepted Answer

The two genes that are closest together are gene A and gene B because we see the lowest frequency of recombination between them (15% or 0.15). This means they are likely closer together on the chromosome. One option is to assume that there are no double crossovers, which would give us a distance of 3 map units between genes A and B (since we see 15% of progeny with recombination between those two genes). While it's possible that double crossovers occurred, we don't have evidence for that, so we can't reliably calculate a longer or shorter distance.

Please Use the Following Information to Answer the Question(s) Below