Horizontal gene transfer can occur through several mechanisms. Why is this relevant to humans?

A. Bacteria are never beneficial to humans.

B. Bacteria can exchange genes for resistance to antibiotics in this way.

C. Bacteria can divide quickly using binary fission.

D. Viruses can infect bacteria, inserting their genetic material into the bacterial DNA.

B

Explanation:

Horizontal gene transfer is the transfer of genes across a generation as opposed to down generations in vertical gene transfer. Bacteria can transfer gene horizontally through mechanisms such as transformation and transduction. The 'male' bacteria develops pili that it inserts into the 'female' bacteria and transfers some genes. This result in recombinant DNA that confers some of the beneficial characteristics to the 'female' bacteria that were there in the 'male' bacteria. This is how a population of bacteria can develop resistance to an antibiotic really fast.