Final answer:
Horizontal gene transfer is the mechanism by which genes are transferred between different species.
Step-by-step explanation:
Horizontal gene transfer refers to the mechanism by which genetic material is transferred between different species by methods other than vertical transmission from parent to offspring. In the context of the spread of antibiotic resistant genes within a bacterial population, horizontal gene transfer allows bacteria to acquire antibiotic resistance genes from other bacteria. This transfer can occur through processes such as conjugation, generalized transduction, specialized transduction, or transformation.
For example, during bacterial conjugation, an F plasmid containing an antibiotic resistance gene can be transferred from a donor bacteria to a recipient bacteria. This results in the recipient acquiring the antibiotic resistance gene and becoming resistant to the antibiotic.
Overall, horizontal gene transfer plays a significant role in the spread of antibiotic resistance and contributes to the emergence of antibiotic-resistant pathogens.