Eukaryotic genomes are much more complex than prokaryotic genomes.
And further, plant genomes are more complex than other eukaryotic genomes. Prior to the development of recombinant DNA technology genomes, were analyzed by reassociation kinetics techniques. Reassociation kinetic experiments are performed by melting DNA and allowing it to reanneal upon itself or with another population of either DNA or RNA molecules. The kinetics of the reassociation provide data that can be used to analyze the overall structure, evolution and expression of genomes. The most common method is by measuring the absorbance change in the ultraviolet region at 260 nm.