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This chapter in biology has been all about the genetics of viruses and bacteria. One of the topics that we covered in class was horizontal gene transfer, in which genetic information is trasnferred between bacterial cells. This leads to increased genetic variation. I found the picture below to be helpful in understanding the difference between horizontal and vertical gene transfer.

According to my article, it was originally thought that horizontal gene transfer in bacterial cells only occurred in certain situations, such as in the presence of strong antibiotics. In actuality, prokaryotes (which include bacteria and archaea) are able to receive genes rather frequently either through a bridge or a virus. This can even occur when the two prokaryotes transferring genes are from different species. Researchers have found that 88 to 98% percent of new genes in bacteria come from horizontal gene transfer. The genes that are transferred are usually next to genes that are not similar in function. Genes that evolve within a bacteria are often located near genes that serve similar functions. The study shows that the majority of new DNA in bacteria comes from horizontal gene transfer. It has also been observed that newly transferred DNA usually stay longer within the genome and evolve more efficiently. Overall, horizontal gene transfer allows prokaryotes to evolve quickly to fit a new environment. This is also the cause of rapid development of antibiotic resistance in bacteria.

To access the article from which I retrieved my information, click here.