Do bacteria have introns?

They're called group II introns, and everybody above is right but wrong, no introns are found in highly conserved genes, but they can be found in other parts of the genome.





Read on:





Where are group II introns found?





Mitochondria and chloroplasts...








Bacteria





In bacteria, about one quarter of genomes contain group II introns, and the bacterial introns differ in several respects from the organellar group II introns. The bacterial introns are not located in conserved genes, but instead are located in mobile DNAs such as plasmids, IS elements or pathogenicity islands. The introns are often inserted outside of ORFs, and almost all introns identified so far encode reverse transcriptase ORFs and are either active retroelements or derivatives of retroelements. For these and additional reasons (see Dai and Zimmerly, 2002) we have proposed that group II introns in bacteria behave mainly as retroelements, a significant difference from organellar group II introns.





Archaebacteria





One recent exciting discovery is that group II introns are present in archaebacteria, where they are found in three Methanosarcina species. These archael introns are closely related to group II introns in eubacteria, but there are differences in their insertion patterns. None of the archael introns are located in cellular genes, but are instead inserted into other introns, forming “twintrons” with up to four sets of nested introns. Moreover, a number of the introns do not encode RT ORFs but seem to be mobile nevertheless. (See Dai %26amp; Zimmerly 2003 for detailed information)

Do bacteria have introns?
I don't think so
Reply:No, I believe that, in general, only eurkaryotic cells have introns. I say "in gereral" because I wouldn't be surprised if they have found some bacterial species which has demonstrated intron-like behavior in some of their DNA.


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Revising my answer to YES!!


As I suspected, there has been recent evidence of Group II introns in bacteria - check the source link.


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In response to frederickman...


Bacteria do not have mitochondria nor chloroplasts. They do, however, have introns as described in the Nature article below. They may not be associated with conservative genes like Eukaryotic cells, but the answer to this thread is unequivocally "YES", bacteria do have introns.
Reply:NO.
Reply:No- bacteria respond to environmental conditions to express genes. For example, if lactose isn't in the environment, the bacterium won't waste energy expressing an enzyme to break down lactose. They use a system of operons and repressors.
Reply:nope
Reply:Interesting question. I would say that when a virus inserts genetic instructions into a bacterial genome you may be able to call that intronic, but generally, bacterial genomes are highly conserved, having not the room or energy for intronic space.
Reply:While there are distant exceptions to the basic answer (as there always are), for all intensive purposes: No. Bacterial DNA does not contain introns and thus no splicing is necessary after transcription/before translation of mRNA.

yoga