Give scientific reasons : Linkage and crossing over of genes are alternatives of each other.
The gene for haemophilia is present on $X$-chromosome. $A$ male has only one $X$-chromosome which he receives from his mother and $Y$-chromosome from father. The human male passes the $\mathrm{X}$ chromosome to his daughters but not to the male progeny (son).
On the basis of Mendel's work which of the following laws were formulated?
$I.$ Linkage
$II.$ Segregation
$III.$ Incomplete dominance
$IV.$ Independent assortment
Choose the correct option
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 $B$
The percentage of crossing over will be more if
For the preparation of genetic maps, the recombination frequencies between genes are additive over short distances but not over long distances due to