3 ms·

My impression is that virus evolution is much slower than bacterial evolution. They can't reproduce sexually, so there is no gene recombination to spread benefi

by tgb 10y ago

My impression is that virus evolution is much slower than bacterial evolution. They can't reproduce sexually, so there is no gene recombination to spread beneficial mutations. This difference is partly why vaccines are done for viruses and not so much for bacteria.

Retric 10y ago
No, there are plenty of bacterial vaccines. ex: https://en.wikipedia.org/wiki/Typhoid_fever https://en.wikipedia.org/wiki/Typhoid_fever
maxerickson 10y ago
The flu vaccine is seasonal because it evolves so quickly. Same with HIV, a high mutation rate complicates making a vaccine. I was really struck by this part of The Great Influenza: https://books.google.com/books?id=BYsW6qTP0pMC&lpg=PP1&pg=PA105#v=onepage&q=mutate&f=false https://books.google.com/books?id=BYsW6qTP0pMC&lpg=PP1&pg=PA... Influenza is an RNA virus. So is HIV and the coronavirus. And of all RNA viruses, influenza and HIV are among those that mutate the fastest. The influenza virus mutates so fast that 99 percent of the 100,000 to 1 million new viruses that burst out of a cell in the reproduction process are too defective to infect another cell and reproduce again. But that still leaves between 1,000 and 10,000 viruses that can infect another cell.
- tgb 10y ago
  This is very interesting, however, is it answering the right question? HIV and flu vaccine are specifically called out as having unusually high mutation rates. Apparently the difference is between RNA viruses and DNA viruses - the RNA ones have no "double checking" to repair errors, so have much higher mutation rates. The rates quoted here [1] put DNA viruses as similar to humans. I don't know if these phages are RNA or DNA ones (Wikipedia says there are phages of both types and while the T4 virus they have a picture of in the article appears to be DNA-based, they probably just chose it for its striking appearance). More importantly - is mutation rate what we want to consider? Bacteria exchange DNA with each other through horizontal gene transfer and Wikipedia quotes that as the main means of transmitting antibacterial resistance, for example [2], even across species (to the extent that bacterial species are even well-defined). I'm not sure how to make the comparison with that to viral mutation rates. This [3] source gives the following interesting, but imprecise, quote: > This antagonistic coevolution results from the constant emergence of countermeasures by which bacteria resist phages, while phages, mutating at a more rapid rate than their prey, find means to overcome this resistance. The paper it cites [4], definitely shows phage evolution alongside bacteria evolving counter-measures. So I think that's enough to answer the original question posed, though the question of "which is evolving faster" is harder to answer and probably isn't very well-posed. That all said, I know nothing about this field and would be happy for some better insight. [1] http://www.nature.com/nrmicro/journal/v11/n5/box/nrmicro3003_BX1.html http://www.nature.com/nrmicro/journal/v11/n5/box/nrmicro3003... [2] https://en.wikipedia.org/wiki/Horizontal_gene_transfer https://en.wikipedia.org/wiki/Horizontal_gene_transfer [3] http://cid.oxfordjournals.org/content/48/8/1096.full http://cid.oxfordjournals.org/content/48/8/1096.full [4] http://rspb.royalsocietypublishing.org/content/royprsb/269/1494/931.full.pdf http://rspb.royalsocietypublishing.org/content/royprsb/269/1...
  - maxerickson 10y ago
    More importantly - is mutation rate what we want to consider? I think it is quite important when considering this particular interaction. Horizontal gene transfer will help a population of bacteria share a successful strategy, rampant mutation will help the virus try more strategies. The article mentions that the particular infection reached a balance with the phage overnight, so it is likely to be a quite an issue. But the population of bacteria resistant to the phage had become susceptible to an antibiotic (for reasons related to the resistance). So it can still be a valuable tool, even if resistance happens quickly.
carbocation 10y ago
Viral evolution (for some strains) is much faster than that of bacterial evolution, if by "evolution" you mean mutation frequency. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC46468/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC46468/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3342999/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3342999/
- tgb 10y ago
  Interesting, thanks. Is there an explanation of why?
  - danieltillett 10y ago
    The rate of evolution is proportional to the population size. For every bacteria there are around 10 phages.
  - arrosenberg 10y ago
    Broadly speaking, most viruses have no mechanism to control mutations other than becoming inactive/nonfunctional. Some bacteria are also like this, in that they can tolerate a high mutation rate without going extinct, while other bacteria have rudimentary control mechanisms that slow their mutation rate in favor of higher survivability and specialization.
rdtsc 10y ago
I thought it was the opposite, that's partly why phage therapy works, as I understand it.

by tgb 10y ago

Retric 10y ago

No, there are plenty of bacterial vaccines. ex: https://en.wikipedia.org/wiki/Typhoid_fever https://en.wikipedia.org/wiki/Typhoid_fever

maxerickson 10y ago

The flu vaccine is seasonal because it evolves so quickly. Same with HIV, a high mutation rate complicates making a vaccine. I was really struck by this part of The Great Influenza: https://books.google.com/books?id=BYsW6qTP0pMC&lpg=PP1&pg=PA105#v=onepage&q=mutate&f=false https://books.google.com/books?id=BYsW6qTP0pMC&lpg=PP1&pg=PA... Influenza is an RNA virus. So is HIV and the coronavirus. And of all RNA viruses, influenza and HIV are among those that mutate the fastest. The influenza virus mutates so fast that 99 percent of the 100,000 to 1 million new viruses that burst out of a cell in the reproduction process are too defective to infect another cell and reproduce again. But that still leaves between 1,000 and 10,000 viruses that can infect another cell.

tgb 10y ago
This is very interesting, however, is it answering the right question? HIV and flu vaccine are specifically called out as having unusually high mutation rates. Apparently the difference is between RNA viruses and DNA viruses - the RNA ones have no "double checking" to repair errors, so have much higher mutation rates. The rates quoted here [1] put DNA viruses as similar to humans. I don't know if these phages are RNA or DNA ones (Wikipedia says there are phages of both types and while the T4 virus they have a picture of in the article appears to be DNA-based, they probably just chose it for its striking appearance). More importantly - is mutation rate what we want to consider? Bacteria exchange DNA with each other through horizontal gene transfer and Wikipedia quotes that as the main means of transmitting antibacterial resistance, for example [2], even across species (to the extent that bacterial species are even well-defined). I'm not sure how to make the comparison with that to viral mutation rates. This [3] source gives the following interesting, but imprecise, quote: > This antagonistic coevolution results from the constant emergence of countermeasures by which bacteria resist phages, while phages, mutating at a more rapid rate than their prey, find means to overcome this resistance. The paper it cites [4], definitely shows phage evolution alongside bacteria evolving counter-measures. So I think that's enough to answer the original question posed, though the question of "which is evolving faster" is harder to answer and probably isn't very well-posed. That all said, I know nothing about this field and would be happy for some better insight. [1] http://www.nature.com/nrmicro/journal/v11/n5/box/nrmicro3003_BX1.html http://www.nature.com/nrmicro/journal/v11/n5/box/nrmicro3003... [2] https://en.wikipedia.org/wiki/Horizontal_gene_transfer https://en.wikipedia.org/wiki/Horizontal_gene_transfer [3] http://cid.oxfordjournals.org/content/48/8/1096.full http://cid.oxfordjournals.org/content/48/8/1096.full [4] http://rspb.royalsocietypublishing.org/content/royprsb/269/1494/931.full.pdf http://rspb.royalsocietypublishing.org/content/royprsb/269/1...
- maxerickson 10y ago
  More importantly - is mutation rate what we want to consider? I think it is quite important when considering this particular interaction. Horizontal gene transfer will help a population of bacteria share a successful strategy, rampant mutation will help the virus try more strategies. The article mentions that the particular infection reached a balance with the phage overnight, so it is likely to be a quite an issue. But the population of bacteria resistant to the phage had become susceptible to an antibiotic (for reasons related to the resistance). So it can still be a valuable tool, even if resistance happens quickly.

carbocation 10y ago

Viral evolution (for some strains) is much faster than that of bacterial evolution, if by "evolution" you mean mutation frequency. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC46468/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC46468/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3342999/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3342999/

tgb 10y ago
Interesting, thanks. Is there an explanation of why?
- danieltillett 10y ago
  The rate of evolution is proportional to the population size. For every bacteria there are around 10 phages.
- arrosenberg 10y ago
  Broadly speaking, most viruses have no mechanism to control mutations other than becoming inactive/nonfunctional. Some bacteria are also like this, in that they can tolerate a high mutation rate without going extinct, while other bacteria have rudimentary control mechanisms that slow their mutation rate in favor of higher survivability and specialization.

rdtsc 10y ago

I thought it was the opposite, that's partly why phage therapy works, as I understand it.