Linkage, in this biologycal process the association and co-inheritance of two DNA segments occurs because they stay close together on the same chromosome. Recombination is the process by which the two DNA segments become separated during crossing over, which occurs during meiosis state. The existence of linkage and the frequency of recombination allow chromosomes to be mapped to identify the similar positions and distances of the genes and the other DNA sequences on them. For discovering the location and ultimate determine of genes for inherited diseases linkage analysis is also a important key tool.
T.H. Morgan, the scientist who was first studied the phenomenon of linkage with the help of common fruit fly or Drosophila melanogaster.