Frequency of recombination between gene pairs on same chromosome as a measure of the distance between genes to map their position on chromosome, was used for the first time by

The chromosome maps are not accurate maps because

Crossing over causes

The map distance between genes $A$ and $B$ is $3$ units, between $B$ and $C$ $10$ units and between $C$ and $A$ $7$ units. The order of the genes in a linkage map constructed on the above data would perhaps be

In Mendelism, linkage was not observed due to

In order to calculate map distance of genes on a chromosome, one must know the