Some regions of chromosomes are more likely to cross over compared to others. Such a region is called a "hot spot". Gene A and gene B, which are in a hot spot for crossing over, are 5,000,000 bp apart on the same chromosome. Gene C and gene D are also 5,000,000 bp apart but they are not in a hot spot. If you conducted two-factor crosses to compute the map distance between genes A and B and between genes C and D, would the map distances be the same between A and B compared to Cand D? Explain why or why not.

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Biology

Montana

14 October, 20:35

Some regions of chromosomes are more likely to cross over compared to others. Such a region is called a "hot spot". Gene A and gene B, which are in a hot spot for crossing over, are 5,000,000 bp apart on the same chromosome. Gene C and gene D are also 5,000,000 bp apart but they are not in a hot spot. If you conducted two-factor crosses to compute the map distance between genes A and B and between genes C and D, would the map distances be the same between A and B compared to Cand D? Explain why or why not.

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Emely Webster · Answer 1

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Explanation:

If neither of the pairs of genes was in a hot spot, the map distance would likely be the same. However, in this case it is said that although both pairs of genes are 5,000,000 bp apart, genes A and B are present in a hot spot. This means genes A and B are more likely to experience recombination and produce recombinant offspring in the F2 generation due to crossing over. As a result, the map distances for A and B will be larger than the map distances for C and D because a map unit is the number of recombinant individuals divided by the total number of individuals, which is then multiplied by 100. Since a greater percentage of individuals would be recombinant in the F2 generation, A and B will have a larger map distance.