Your Feces Is a Wonderland of Viruses

sciencehabit writes "Thanks to an anlaysis of fecal samples from four sets of Missouri-born female identical twins and their mothers, researchers have concluded that human guts harbor viruses as unique as the people they inhabit; the viral lineup differs even between identical twins. Even more surprising? These viruses may be doing good work inside of us."

Evolution

[dward90]

From my understanding of evolution, I think it would be more surprising if something we all have inside of us was doing something bad.

Re:Yea, and?

[VTI9600]

Uhm, this is rather well known and well established.

I thought it was well known and established that viruses are exclusively parasitic. Now it turns out that some bacteriophages are not only harmless to their hosts, but can actually assist bacteria by exchanging their genetic material, creating an accelerated evolutionary process which results in advantageous mutations to the ultimate benefit of the human host. I'm not sure if this is a new discovery, but it definitely goes against the conventional wisdom.

I'll admit that the title could have been worded better, but still, you should RTFA before criticizing.

Re:So what we are anyway?

[sznupi]

Mass != number of cells. Bacterial ones are typically quite a bit smaller.

Yes, most in gut, but not all - if our immune system was so efficient as you paint it to be, there wouldn't be much infectious diseases to speak of (BTW, up to 1/3rd of world population has just one [wikipedia.org] brain parasite)

Re:So what we are anyway?

[sznupi]

Archamoebae, not at all archaic eukaryotes, don't have mitochondria.

Anyway, not sure why you are hung up on mtichondria so much, it seems mostly as a 'BTW" of above poster - counting bacteria is apparently enough to arrive at higher numbers. Those which live "just" in our skin are very important, too - they compete with more "nasty" ones, keeping their numbers in check, as you mentioned...which means they DO (contrary to what you say just sentence before) interact in a beneficial way with skin or immune system

Intestinal payload also differs between humans. So does "human" DNA. And "actively controlled and purged on cellular level by our immune system" is probably a bit too one-dimensional way of looking at them, considering you'd be dead fairly quickly if you were to lose your bacterial flora.

Re:Evolution

[mldi]

Actually, our rapid development into sterile societies has backfired because of how we're wired due to evolution. At least that's the theory. Our bodies were built to battle a few parasites, at least in our youth, and the theory is that because we are so sterile anymore, our bodies are looking for something to attack... and since in modern countries the majority of the population is parasite-free, they attack us instead. Behold: autoimmune diseases!

It's actually probably pretty good for us to get at least a little down'n'dirty as kids so our bodies don't go crazy attacking perfectly normal things as unwanted foreign bodies.