Two dominant non-allelic genes are $50$ map units apart. The linkage present is:

The distance between two genes in a chromosome is measured in cross-over units,which represent:

In $Drosophila$,crossing over occurs in females but not in males. Genes $A$ and $B$ are located on a chromosome at a distance of $10 \ cM$. The genotype of the female $Drosophila$ is $AB/ab$ and the genotype of the male $Drosophila$ is $AB/ab$. How many types of gametes are produced by the female and male $Drosophila$,respectively?

The coupling and repulsion theory was proposed by:

In order to calculate the map distance of genes on a chromosome,one must know the:

Which of the following statements is $NOT$ true for two genes showing $50\%$ recombination frequency?