Which of the following is NOT a form of bacterial horizontal transfer?

Bacterial replication is indeed not a form of horizontal gene transfer. It is a process by which a single bacterial cell divides to produce two identical daughter cells, primarily for growth and reproduction. This method of replication is vertical transfer, where genetic material is passed down from one generation to the next, maintaining the lineage of the bacteria.

In contrast, horizontal gene transfer refers to the transfer of genetic material between organisms in a manner other than traditional reproduction. This includes transformation, which is the uptake of free DNA from the environment; transduction, which involves the transfer of DNA between bacteria via bacteriophages; and conjugation, where genetic material is exchanged through direct cell-to-cell contact, often involving plasmids. Each of these processes contributes to genetic diversity in bacterial populations and can play a significant role in the spread of antibiotic resistance, virulence factors, and other adaptive traits.