Question: Origin of plasmids

Rafael Maldonado rafael at howard.genetics.utah.edu
Tue Oct 10 18:19:36 EST 1995

On Mon, 9 Oct 1995, Steven Sanyal wrote:

> Most plasmids I have come across thus far have dealt with antibiotic 
> resistance genes - used for selections.  Did these genes evolve only 
> since the advent of antibiotics this century, or is it believed that they 
> existed before?  ie: were their natural antibiotic agents that existed 
> before - a sort of interbacterial warfare.

Sure that resistance genes existed before, since antibiotics existed before 
also. The big problem has been the huge selection we are developed in 
search of the resistant bacteria.

Most of antibiotics used in humans are from fungi. It's supposed that 
bacteria and fungi have had to fight for survival during millions of 
years, and they have created a sophisticated chemical war with 
antibiotics and resistance genes. But now, we are putting in a big struggle
a lot of bacteria, and they are defending creating more resistance 
methods than ever. Probably in the future we will discover genes for 
resistance against antibiotics totally syntethic created by humans.


Rafael Maldonado                             |  La cita ha sido
room 6160 Eccles Institute of Human Genetics |  
Department of Human Genetics		     |  retirada por respeto
University of Utah			     |
Salt Lake City, Utah 84112. USA.	     |  a la propiedad 
Rafael.Maldonado at genetics.utah.edu           |
Rafael at howard.genetics.utah.edu	             |  intelectual.
Tel: 801-581-4429			     |
Fax: 801-585-3910			     |

More information about the Microbio mailing list

Send comments to us at biosci-help [At] net.bio.net