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

When white-eyed and miniature-winged $Drosophila$ $melanogaster$ is crossed with its wild type,it produces which of the following percentages of recombinants (in $\%$)?

Crossing over is

If $F_2$ of a dihybrid cross contains only parental combinations,then Mendel would have discovered .....

The linkage map of a fruit fly has a total map distance of $66$ units. The gene for yellow body $(a)$ is at one end and the gene for short hair $(y)$ is at the other end. What will be the recombination frequency between these two genes $(a$ and $y)$?

What will be the number of linkage groups in maize if it has $10$ pairs of chromosomes?