Has AIDS evolved?
They can conquer smallpox, so why not AIDS?
Indeed, why not the common cold? Smallpox was (hopefully) overcome by vaccines. These are specific substances which are used to trigger the body’s ‘soldier factories’ into making lots of ‘soldiers’ (antibodies) which are designed to kill only a specific, particular type of virus before it can do much damage. (Smallpox, AIDS and the common cold are caused by various types of viruses—AIDS is caused by a virus called HIV, Human Immunodeficiency Virus.)
The reason why vaccines have not succeeded in eliminating influenza, for example, is because the viruses change. Soldiers trained to attack only enemies in grey uniforms will be useless if the enemy changes into blue uniforms. Effective vaccines against particular strains of flu virus constantly need to be updated for this reason.
The same potential problem plagues the development of an effective vaccine against HIV. As the virus multiplies, the ‘copies’ which are made of it often have copying mistakes (mutations) which can change those parts of the virus that your body’s defences are geared to recognize. Only a very small change may be enough—a change which otherwise is completely irrelevant to the structure or function of the virus. So a ‘new strain’ emerges, and although you were able to fight off the first one, now you can’t.
World Health Problem
It is thought that HIV may have arisen as a problem for humans by just such changes. From a fairly harmless virus infecting the green monkey population in Africa, it has now become a major world health problem for humans.1
Well then, do viruses ‘evolve’? Has HIV evolved? If you define evolution simply as genetic change, the answer would seem to be yes. But does this give us evidence for the evolution of all living things on earth from humble beginnings (e.g. an amoeba) to man and other organisms living today, which are therefore all related by common descent? After all, this is what people mean by the word ‘evolution’.
This issue is important when considering all types of observed changes in living things, including speciation in fruit flies, for example.
Are the observed changes, on analysis, heading in the ‘right direction’? That is, are they the type of changes which, given enough time, would be capable of producing a massively complex organism like a horse from a one-celled creature? If they are not, it is misleading to call such changes ‘evolution’. Should we call them ‘micro-evolution’? This may be technically correct, and a proper term for creation scientists to use. However, at the risk of semantic hair-splitting, I suggest that what most people understand by the word ‘micro-evolution’ is ‘a little bit of that which would, given enough time, cause real macro-evolution’.
A small example may help here. Let’s say that you are on the first floor of a building and you find there is a baby kangaroo on the same floor. You and a friend are arguing as to whether he could have come up via the stairs. To obtain evidence to make this explanation plausible, it would certainly help if you could demonstrate the animal’s ability to hop from one step to the next higher one. But to observe its ability to hop horizontally across the room tells you nothing at all about the question being contemplated. ‘Evolution’ to most people means ‘hopping up the stairs’. So if hopping across the room and down the stairs is labelled ‘micro’ or ‘mini’ evolution or whatever, it risks being misleading.
Observed changes in viruses, even if these involve the conversion of a harmless virus into, say, the deadly AIDS virus, cannot, in terms of the above discussion, be called ‘evolution’, as we will see.
To understand why, we first need to look into what a virus really is. We may regard a living cell (for example, a cell in your skin or liver or other tissue, or a bacterial cell) as a very, very complex chemical factory. This factory is capable of many functions, including that of reproducing itself. Directing all this machinery is a blueprint, which is the coded information contained in the molecule, DNA. A virus is very different—it consists of a small amount of this ‘blueprint’ material (DNA or RNA). Note that it has no ‘factory’ of its own—it cannot move itself, it has no power source, and it has no machinery with which to duplicate itself.
By means of simple chemical programming, it’s able to latch on to a cell wall. The material it contains is automatically released into the cell, and the information on the ‘blueprint’ takes over and starts to direct the cell’s factory, which starts to manufacture many copies of the virus.
Package with a Code
The cell eventually swells and bursts, releasing lots of new viruses to start the process all over again.2 So we see that a virus is nothing much more than a package containing a code, which takes over from the cell’s code so that the cell then makes more code-containing packages. The cell is destroyed in the process.
Many semantic arguments have raged over whether a virus can be called a living thing or not. This is one reason why many people feel it is sort of ‘half and half’—therefore a good candidate for a kind of transitional stage between life and non-life.
Whether you call it living or not is a matter of definition, but I hope to demonstrate that however you define life, the virus can in no way be used as an evolutionary ‘intermediate’. The reason is simple—it needs to have all the complex machinery of a living cellular organism available to it! Without a fully functioning, living cell, the virus cannot reproduce (or should we say, arrange its own reproduction).
So, regardless of your ideas about either evolution or creation, a virus will not be able to exist before a cellular creature is on the scene. Viruses do not really fit anywhere on the evolutionary ‘tree of life’. They cannot represent ‘early forms of life’ because they can only multiply within living cells. This ‘chicken and egg’ problem is often overlooked. They obviously could not, therefore, have been the ancestors of one-celled creatures, and it is difficult to see how they can be their evolutionary descendants.
So we see, then, that any changes which might occur in viruses have very little, if any, apologetic value for evolutionists trying to show us how a fish supposedly changed into an amphibian, for instance.
Wouldn’t a change in a disease-causing agent, converting it from a minor nuisance to a serious health threat, be a major evolutionary step? Surely, say some, this could not be labelled ‘horizontal change’ or ‘change within the kind’? Once again, though, we will see that this has little relevance to evolutionary apologetics.
To assess the significance of any genetic change (real or proposed) as an argument for the idea of ‘vertical evolution’ (that is, change to a higher overall level of complexity) we must look at the informational change required. Thus, for evolution to have converted a reptile into a bird, we can tell by looking at the gross morphological and physiological differences that the amount of new highly ordered genetic information required would be incredibly large.
The same would be true of every significant step along the way—it requires the addition of new, teleonomic (project-oriented) genetic information. Such information would reflect the required increase in functional complexity. When we discuss disease-causing agents, we need to remember a few things about the ability of such an agent (not just viruses) to infect. These include its ability to withstand host defences—for example, immunologic mechanisms, antibiotics and antisepsis. Thus, the informational change required may be very small, ‘horizontal’ if you like, even though it has a major impact on us as sufferers of disease.
Life and Death
For example, the bacterium Staphylococcus aureus may exist as penicillin-sensitive and penicillin-resistant strains. From all other standpoints, they are identical—such as their morphology. They are even classified as the same species. But to a human being suffering from a Staph infection who has access only to penicillin, the difference may be one of life or death.
Someone may say at this point—isn’t there a vast informational difference between the two? After all, the resistant strain has the genetic information necessary to produce penicillinase, which is a complex chemical.
However, the sensitive strain may have this same information, only that it has not been ‘switched on’, or else the resistant strain has gained its information in toto by a special transfer process from an already resistant one. Here also, the complex information has not ‘evolved’, but was already there.
Incidentally, the reason why it is much easier to have an antibiotic against a bacterium than against a virus is because it is possible to find or design a chemical which throws a ‘spanner’ in the machinery of a bacterium without doing the same for the machinery of the human cells it infects. Because, as we have seen, a virus uses the human’s machinery, it is extremely hard to do anything to destroy viruses without at the same time destroying the cells of the human host.
Alteration To Coat
Returning to our main point about viruses, a virus may need only a slight variation in its protein coat to alter the way it is recognized by the body’s defence mechanisms. Consider a population immunized against an otherwise deadly virus, which we will call ‘V1’. Now suppose that a mutation manages to cause a slight transformation in the protein coat of one of these viruses by interfering with the sequence of letters in the alphabet of the genetic code. Let’s call the new virus strain ‘V2’. In all other respects, these two are identical. Nothing new in the way of complexity has been added, but this minor structural change causes the body’s immune defence mechanism not to recognize it as V1. Before a new vaccine has been developed and put into use, it wipes out millions of people. Emotionally, people would assess this as a change of major proportions.
Therefore we see that in micro-infective agents, minor genetic shifts can easily have catastrophic consequences out of proportion to the actual change in informational content. When compared to the usual, supposed evolutionary transformations in ‘higher’ creatures we can easily see that there is no comparison left at all, in spite of the obvious favourable selection which occurs.
- Viruses can have no evolutionary relationship to any other form, and so whatever may have happened to say, the AIDS virus, has no relevance to the supposed history of truly living organisms in any case.
- An apparently major effect is probably caused by only a horizontal or even a negative change in informational content, and therefore does not relate to the sort of evolution postulated generally. It certainly does not involve any increase in functional complexity.
So to answer the question posed by the title of this article, while viruses may change considerably, and while the AIDS virus may have changed its infectivity, it is certainly not the type of change, in quality or direction, which would or could cause that virus to become a totally new, more complex type of living organism. In that sense, AIDS has not evolved.
Long after this article was published, the PBS/SBS Evolution series used HIV/AIDS as ‘proof’ of evolution. Yet the new data has done nothing to make the principles in this article obsolete. Rather, in one case, HIV resistance to drugs was clearly caused by a deleterious mutation, as shown by their inability to cope with the ‘wild’ type when the drugs were removed; and immunity to AIDS can be conferred by a mutation that causes loss of certain receptors on the immune cells preventing the HIV from docking on them.
- It is theoretically possible that AIDS may always have been present in a human population that was naturally immune. Return to text
- Many animal viruses, particularly the para-influenza group, produce no obvious change in the infected cell. Return to text