Discuss in detail the contributions of Morgan and Sturtevant in the area of genetics.

(N/A) Experimental verification of the chromosomal theory of inheritance was done by Thomas Hunt Morgan (Father of experimental genetics) and his colleagues. It led to the discovery that the basis of variation is sexual reproduction.
Morgan worked with the tiny fruit flies,$Drosophila$ $melanogaster$,which were suitable for such studies. Morgan performed dihybrid crosses in $Drosophila$ to study sex-linked genes. The crosses were similar to the dihybrid crosses carried out by Mendel in peas. For example,Morgan hybridized yellow-bodied,white-eyed females with brown-bodied,red-eyed males and intercrossed their $F_1$ progeny.
He observed that the two genes did not segregate independently of each other,and the $F_2$ ratio deviated significantly from the $9:3:3:1$ ratio (expected when the two genes are independent).
Morgan and his group knew that the genes were located on the $X$ chromosome and observed that when two genes in a dihybrid cross were situated on the same chromosome,the proportion of parental gene combinations was much higher than the non-parental type.
Morgan attributed this to the physical association or linkage of the two genes. He coined the term 'linkage' to describe this physical association of genes on a chromosome and the term 'recombination' to describe the generation of non-parental gene combinations.
His student,Alfred Sturtevant,used the frequency of recombination between gene pairs on the same chromosome as a measure of the distance between genes and 'mapped' their position on the chromosome.
Today,genetic maps are extensively used as a starting point in the sequencing of whole genomes,as was done in the case of the Human Genome Sequencing Project.