In the figure above,a new beneficial allele,B,arises on a chromosome containing the ordered loci A,B,C,D,and E,depicted in the top panel.After reproduction,those chromosomes possessing the B allele increase in frequency.Over time,recombination breaks up the association of the B allele with the A,C,D,and E alleles.Assuming that the five loci are spaced evenly along the chromosome,the first pair of allele combinations to be broken up will be
A)B and A.
B)B and C.
C)B and D.
D)B and E.
E)All alleles will break up at an equal rate

Question

In the figure above,a new beneficial allele,B,arises on a chromosome containing the ordered loci A,B,C,D,and E,depicted in the top panel.After reproduction,those chromosomes possessing the B allele increase in frequency.Over time,recombination breaks up the association of the B allele with the A,C,D,and E alleles.Assuming that the five loci are spaced evenly along the chromosome,the first pair of allele combinations to be broken up will be
A)B and A. 
B)B and C. 
C)B and D. 
D)B and E. 
E)All alleles will break up at an equal rate

Quizplus · Accepted Answer

Recombination breaks up the association of the B allele with the other loci along the chromosome. Since the loci are spaced evenly along the chromosome, the first pair of alleles to break up will be the ones that are closest together. In this case, B and E are the closest together, leading to their separation being the first to occur. Therefore, the answer is D.

In the Figure Above,a New Beneficial Allele,B,arises on a Chromosome