Definition of Horizontal Gene Transfer
Horizontal gene transfer is defined as the transmission of DNA from one individual to another individual. These two individuals should not be having a parent-offspring relationship. It is also known as lateral gene transfer. This transfer of gene also takes place between different species as in the case of prokaryotes and eukaryotes.
On the contrary, when the DNA is transmitted from the parents to their offspring, it is termed as vertical gene transfer. The phenomenon of horizontal gene transfer is more complex in eukaryotes as compared to the prokaryotes. This also helps us in understanding the concepts of adaptations and evolution.