Define/Explain: Linkage.

Select the correct statement from the ones given below with respect to dihybrid cross.

Genetic variation is observed in sexually reproducing species.

The lack of independent assortment of two genes $A$ and $B$ in the fruit fly $Drosophila$ is due to:

In a certain plant, red flowers $(R)$ are dominant to white flowers $(r)$ and tallness $(T)$ is dominant to dwarfness $(t)$. $A$ heterozygous plant $(RrTt)$ is backcrossed with a double recessive plant $(rrtt)$. If the gene loci for colour and size are situated very close together on the same chromosome, the expected percentage of offspring could be approximately:

Tall Red

Tall White

Dwarf Red

Dwarf White

respectively.

When closely placed genes on the same chromosome are inherited together,the phenomenon is known as: