Talk:Horizontal gene transfer in prokaryotes
START WITH THIS PARAG? rewritten some way?:
In the years 1987-1996 in Vietnam there was a medically alarming appearance of resistance to the antibiotic chloramphenicol appeared in the Gram negative aerobic meningococci bacteria causing infectious meningitis, hampering the treatment of the disease in that country. Subsequent laboratory investigations revealed that the gene conferring chloramphenicol resistance on meningococcus bacteria was identical to a previously identified mobile gene named Tn4451 found in the completely different Gram positive bacterium known as Clostridium perfringens . This episode is but one illustration of the extensive movement of genes that takes place between distantly related microbes, a process given the technical name of horizontal gene transfer.
Horizontal gene transfer (HGT; also called lateral gene transfer, LGT) is thus defined as movement of genes between different species, or across broad taxonomic categories.
As indicated by the opening example, HGT is common among Bacteria and Archaea, even between very distantly-related species. (Both these two categories of microorganism lack distinct nuclear compartments for their DNA, and are thus classified as Prokaryotes, meaning possessing a primative nucleus, in contrast to cells which possess well formed nuclei, the Eukaryotes.)
But besides occurring in the prokaryotes, HGT occurs in eukaryotic protist microorganisms, and in both pathogenic and non-pathogenic microorganisms and is a major feature of natural microbial evolution.
Detailed and comprehensive DNA sequence analysis of many prokaryotic cell genomes has shown that these genomes generally consist of a conserved backbone of mainly housekeeping genes that is subject to interruption by islands of DNA. These DNA islands can change relatively frequently during prokaryote evolution due to insertion, deletion and replacement events involving by foreign DNA.Studies of antibiotic resistance genes provide convincing evidence for wide transmissibility of genes between taxonomically diverse microbial species.
- Luria, S. E. (1947) Recent advances in bacterial genetics. Bacteriological Reviews 11, page 1.
- Galimand M, Gerbaud G, Guibourdenche M, Riou JY, Courvalin P.(1998) High-level chloramphenicol resistance in Neisseria meningitidis. N Engl J Med. 1998 Sep 24;339(13):868-74. Erratum in: Engl J Med 1999 Mar 11;340(10):824.Comment in: N Engl J Med. 1998 Sep 24;339(13):917-8.