Sex linkage was first observed by.....

$A$ scientist performed a gene mapping experiment in maize. He mapped genes on chromosomes based on the percentage of crossing over between different genes. One map unit corresponds to $1\%$ crossing over or recombination frequency. Based on the study of crossing over in maize, the scientist observed the following recombination percentages between genes $A, B, C,$ and $D$: $A$ and $D = 10\%$, $A$ and $C = 3\%$, $C$ and $D = 7\%$, $A$ and $B = 5\%$, and $C$ and $B = 8\%$. Based on these observations, determine the correct order of genes $A, B, C,$ and $D$ on the chromosome.

When linked characters or genes are inherited together through two or more generations,it is called

Frequency of crossing over in a chromosome is an index of

Which of the following does not follow the law of independent assortment?

How many types of gametes will be produced by a male Drosophila having the following arrangement of two genes ($y$ and $w$) on the $X$-chromosome?