Gene can be defined as

In Mendelism, linkage was not observed due to

Two heterozygous parents are crossed. If the two loci are linked what would be the distribution of phenotypic features in $\mathrm{F}_{2}$ generation for a dihybrid cross?

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

Linkage in Drosophila was first discovered by

The linkage map of $X$-chromosome of fruit fly has $66$ units with yellow body gene $(y)$ at one end and bobbed hair $(b)$ gene at the other end. The recombination frequency between these two genes ($y$ and $b$) should be