It turns out that the bacteria that gave you a fever may just be lusting on another one of its kind.
Yes, bacteria do have sexual intercourse, said Dr. Rosie Redfield, a microbiology professor from the University of British Columbia, in a lecture titled “Do Bacteria Have Sex?” at the Morrill Science Center yesterday afternoon.
“Sexual reproduction in bacteria is very ancient,” Redfield said.
But contrary to what many scientists purportedly believe, Redfield found out in her research that there is no evidence that proves that bacterial sex promotes recombination, which is the alteration of the genetic structure of microorganisms (such as bacteria) for natural selection and adaptation.
Redfield said that bacterial reproduction only happens for processes involving the bacteria’s DNA, such as replication and repair. Recombination, on the other hand, is only a side effect of the sexual process, she said.
Bacteria can have sex through conjugation, a process through which two bacteria join to produce another cell and exchange genetic information, Redfield said. Yet, she said, there is still no concrete evidence that conjugation promotes recombination, and that scientists have yet to unravel its mysteries.
In addition, a bacterium can also have sex on its own, Redfield added. She called this kind of sex a “parasexual process,” through which a bacterium would not need a partner to acquire genetic materials. One prominent example of this is the process of transformation, in which a bacterium ingests stray DNA from the environment.
But the reason behind transformation is not the need for recombination, Redfield emphasized. Instead, DNA strands serve as bacteria’s food. DNA is rich in carbon, nitrogen and phosphates that help to maintain processes in the cell.
Upon ingestion, the strands degrade. The information carried by the DNA does not, though. The bacterium incorporates this genetic information into its own, causing changes in its genetic structure accidentally, Redfield said.
“This is … evidence that DNA uptake is a sexual process,” she said.
Furthermore, Redfield found out in her research that a cell undergoes transformation when it needs nutrition. A material called CRP indicates to the cell that it needs food, she explained. It then joins with another material called SXY to start the DNA uptake.
Most bacteria would pick up any DNA that they find, Redfield said. But a certain type of bacteria called Haemophilus is pickier.
According to her research, the Haemophilus Influenzae bacterium, which causes bacterial meningitis in children, prefers a specific DNA pattern. Redfield called this instinct the cell’s molecular drive.
Still, Redfield said that the recombination that results from transformation is purely accidental.
On the other hand, Redfield said that these processes can still result to evolution in some species, only it would take them at least one million years.
Redfield has been a microbiology faculty member in the University of British Columbia since 1990. She also runs the university’s Redfield Lab, and owns RRResearch.com, a blog that includes developments in her work.
Ardee Napolitano can be reached at [email protected]
