The chromosome maps are not accurate maps because

Alleles of different genes that are on the same chromosome may occasionally be separated by a phenomenon known as

Given below are two statements : one is labelled as Assertion $(A)$ and the other is labelled as Reason $(R)$.

Assertion $(A)$:

Mendel's law of Independent assortment does not hold good for the genes that are located closely on the same chromosome.

Reason $(R):$

Closely located genes assort independently.

In the light of the above statements, choose the correct answer from the options given below:

Give scientific reasons : Linkage and crossing over of genes are alternatives of each other.
 

Genes $A, B$ and $C$ are linked. Genes $A$ and $B$ are more close than $A$ and $C.$ Find out the correct option for the given statements

$I.$ $A$ might be before $B$ and $C$

$II.$ $B$ might be between $A$ and $C$

$III.$ $C$ might be between $A$ and $B$

$IV.$ More crosses has occurred between $A$ and $C$ than $A$ and $B$