A pre-medical university student is trying to get into professional medical school?
Who is their best competitor?
a) Another pre-medical student
b) An engineering student
c) A arts student
d) A music student
e) A high school student
f) A chimpanzee
What is closest to you but not the same as you is likely to be your most able competitor.
Bacteria are almost perfect Darwinists
When you combine these two above statement the logical conclusion is that subgroups within a bacterial species are their own worst competitors/combatants both on and off the host.
Restriction endonuclase and DNA modification systems are weapons in this battle, both for theft and to prevent theft of genetic material and to prevent anticompetitve effects based on DNA.
Looking cds based genome alignments of different sero groups of Actinobacillus pleuropneumoniae it is evident that the sero groups are indeed geneticly distinct but highly related AND they all have BOTH similar but distinct DNA restriction systems and unique restriction systems.
If it is all one big happy family why would this be so?
If you consider that restriction endonucleases are a bacterial defense against viruses, then the similarities and differences between closely related bacteria can be viewed in Darwinian terms as common descent with modification due to natural selection and/or genetic drift.
No doubt restriction enzyme systems are "immunity" against the viruses, but viruses also bring new genetic information which can be advantageous. To view bacterial viruses as a disease is too simplistic IMO.
Many bacteria are naturally competent which means they have systems to scavenge genetic information that may be useful. The restriction systems make sure the genetic uptake is on their own terms. Both genes and bacteria are selfish.
PS. Looking at the case of A pleuopneumoniae serotypes, a good proportion of divergence is in restriction systems, both in presence /absence and levels of divergence probably too high to be drift and much much higher than elsewhere in the genomes.
Looks like one big unhappy family to me
RE will allow the bacteria to uptake genes without suffering from the phage, a digested phage DNA is much less likely to create new phages... Continuing on the beginning of the discussion - a bacteria is not likely to 'want' to share a good gene with its peers, if the phage gets restricted its a win-win situation for the bacteria...
Talking on RE and bacteria - any idea how does Diplococcus pneumoniae G41 (the bacteria that produce the DpnI RE that cut methylated DNA) deal with DNA methylation?
Additional information:
What are the most profitable human businesses after war, addictive substances, slavery and womens cosmetics?
I would guess theft in its many forms.....
How did the banking industry at least semi-successfully combat theft. They made robbing a bank cost more than the money able to be stolen.
Acquiring the right gene at the right place and the right time is a monumental event for a bacterial group competing for precious access to animal hosts.
It seems this would probably be sufficient for natural selection of systems to do just that and perhaps prevent just that. As both genes and bacteria are selfish, they would only want exactly the right gene at exactly right time, hence too much gene transfer is just as bad as too little.
My thoughts are that the divergent DNA regions of groups of closely related but distinct bacteria groups that contain genes directed at uptake, modification and restriction of DNA are part of all this.
Well this depends on how you see selection... Does the bacteria have a say on the issue or is it simply a "selfish gene" case. Think about the F' plasmid for example, what is the benefit for the bacteria? There is a clear benefit for the F' plasmid though.
- Badges
- Science topic
- Similar topics
- Biological Science
- Molecular Biology
- Biomolecules
- Nucleic Acids
- DNA