PLEASE HELP 1 Genes A B and C are on a chromosome as shown b

PLEASE, HELP!

1) Genes A, B, and C are on a chromosome as shown below.

A--------- 10 million bp ---------B------------------ 20 million bp ------------------C

Is this a physical or linkage map? Would you expect the distance between A and C to be more, less or equal to the sum of the distance between each of the outside markers and the middle gene (A-B + B-C)? Why?

2) Genes A, B, and C are on a chromosome as shown below.

A---------10%---------B------------------20%------------------C

Is this a physical or linkage map? Would you expect the percentage of recombination between A and C to be more, less or equal to the sum of the recombination frequencies between each of the outside markers and the middle gene (AxB + BxC)? Why?

Solution

1) Genes A, B, and C are on a chromosome as shown below.

A--------- 10 million bp ---------B------------------ 20 million bp ------------------C

This is a Physcial map. In physical mapping the distance between A and C is equal sum of the distance between each of the outside markers and the middle gene because of no external forces like interfernce in linkage mapping etc.

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2) Genes A, B, and C are on a chromosome as shown below.

A---------10%---------B------------------20%------------------C

It is a linkage map. The percentage of recombination between A and C to be less, as to the sum of the recombination frequencies between each of the outside markers and the middle gene (AxB + BxC) due to interference.