There have been a number of interesting comments lately here at TSZ that referred to viruses.
Are viruses pre-biotic entities, and did they contribute to the origin of life?
Are viruses alive?
Do viruses evolve?
Are viruses an example of what evolution is capable of?
Did viruses contribute to the evolution of life?
Should be fodder for some discussion.
No. Yes. Yes. Yes. Yes.
Virolution is the definitive guide to this amazing new field of research that has redefined the science of evolution and disease.
Yet another “theory of evolution.”
I am quite sure that our views on evolution would be very different had biologistsw studied genetics and natural selection before and not after most of them were convinced evolution had occurred.
JBS Haldane
Golly, I guess every time anyone learns anything new (or in more depth) about biology, we necessarily get a new theory. And I guess since we keep requiring a new theory every two weeks, we must not actually know anything at all.
This has always been a problem with learning – the more we know, the more we realize we don’t know, and every answer sprouts several new questions. Quite clearly, the solution to this madness is to have a single explanation that applies to everything known and unknown, and cannot be tested (lest we learn something).
Don’t know why anyone should be surprised by that. Hell, monkeys have 19,990 genes.
Dear Flint, It’s ok if you don’t “get it.”
If every discovery requires a new explanation then every discovery requires a new theory.
It just happened, that’s all, leaves a lot to be desired. Don’t you agree?
Mung,
Well, there is also, “nature is just like that.”
So if a frog can forego its lungs during embryonic development, and sidestep natural selection, well, so, nature has ways. Not a problem for the theory!
What theory?
Whether viruses are “alive” or not is an argument that usual bogs down in conflcting definitions, and in the end it is not essential to decide it. But viruses definitely do evolve, and the field of evolutionary virology has been very active, particularly since the 1980s when viruses such as HIV were under intensive study with the DNA sequencing methods that had just become available.
For virus phylogeny the methods used are very similar to those used in other organisms such as bacteria. So viruses make us explore some new methods, but do not massively revise our approaches to molecular evolution. Viruses did make possible collection of complete sequences before this could be done with bacteria or other organisms, simply because their genomes are smaller. They also let us make phylogenies with both present-day and fossil sequences, simply because evolution of RNA viruses such as HIV is very fast, so that those fossils were often available in someone’s freezer.
A colleague of mine, Arno Motulsky, collected 300 blood samples from a hospital in Kinshasa in 1959. After he had used them for studying hemoglobin variants in Africa, he kept the samples frozen. By the 1990s they had been used to find the oldest-ever sample of HIV (one patient of the 300 apparently was infected).
Joe Felsenstein,
Viruses also allowed for creation of known real (not simulated) phylogenies with which to test phylogenetic methods. They work pretty well, it turns out. Joe can you recall any citations to the work? All I remember is that it was done in the Hillis lab.
And everybody.
Whoa. Do viruses evolve? HMMM
If they are not living things then non living things evolve?!
If they do then at what point are they given a new name in bioloy? I presume they have latin names. Is there a list of new viruses around that only evolved in the last 50 year?
if selection affects them and there is a new result does iot mean they evolved? nO its just a new population of a segment of the old.
I guess they might say a virus evolves because it made a new ability to resist a drug etc etc. Hmmm.
It would mean its just using some existing trait and selecting on it.
However much CHANGE a virus does it needs to be shown it could cross thresholds to actually be said to be evolving.
Otherwise is trivial diversity within a type.
People changed colours but people are not evolving or in different directions of evolution from the different colour populations.
Evolutionism is not about mere change but about new traits that can turn a fish into a rhino.
I don’t think mutations could ever turn a virus very much out of its basic type.
In short they don’t evolve.
The trivial change is not accurate sampling to describe them as evidence of evolution.
No, and no respectively.
Yes and no, IMO
Yes
Yes. Are they an example of what The Designer is capable of?
Continually, and in numerous ways, yes of course.
Some would disagree with you there: The ancient Virus World and evolution of cells.
Koonin EV, Senkevich TG, Dolja VV.
Significant chunks of our genome are derived from historic viral infection. Some TEs themselves may have their origins in viruses – or vice versa for that matter. Some such elements make a protein coat, very like those of viruses, even though they never go ‘outside’.
This is not massively helpful to Sal’s thesis that it-might-all-be-functional-you-never-know. It is certainly possible that Design arranged an infection for that very reason – to add function or sequence to the multi-layered fractal informatic integrome that modern science has discovered and Dan Graur hates [sic] … but not very likely.
Rumraket,
LGT between viruses during multiple infections can’t be ruled out.
Let’s not forget that these are all protein coding differences, and hence everything coalesces through LUCA. There isn’t much reason to suppose LUCA was a virus, even if viral and cellular lineages don’t nest neatly subsequently.
But not from you it seems eh Mung?
I’ve gotten the impression, and Koonin sort of confirms this above, that there was a free-for-all of gene swapping in the pre-biotic world among indiscreet entities. Just as the sun, planets and asteroids coalesced out of the protoplanetary disk this prebiotic world coalesced into living cells and viruses more or less at the same time. But it seems to me theres no way to ever know this with any certainty and viruses could just as easily have arisen well after living cells formed
No. Just as computer viruses aren’t computers. Below is the empirical formula for polio virus….enough said
C332,652H492,388N98,245O131,196P7,501S2,340
REW,
It’s a view one hears from time to time – it was discussed recently on the Carl Woese thread – but I don’t think it has much going for it myeself. There are other ways to interpret the apparent ‘rampant HGT’ at the base of the ToL that people invoke in support of these ‘progenote’ ideas.
In order to prosper, a gene needs to be attached to the consequences of its actions in some way.
I understand and I think koonin is sorta playing with the terminology by calling the very early replicator, non-cellular stage of life for a kind of “virus world”.
Ancient retroviruses emerged half a billion years ago