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Counter-Intuitive:
Still Evolving After All These Years

(Part I)

Chris Lawson

For one of the cornerstones of modern science, evolutionary theory has been poorly served by science fiction. Physics, chemistry, and even statistics have been explored by science fiction writers with a bent for accuracy in stories such as "The Cold Equations," The Currents of Space, and The Chain of Chance. Biological science was largely disregarded until the 1970s, and evolution has been almost wilfully misrepresented. Of course, there have always been writers who managed to write "hard" biological stories throughout the history of the genre. To choose a few examples: John W. Campbell's "Who Goes There?" (1938), Olaf Stapledon's Last and First Men (1930), Aldous Huxleys' Brave New World (1946), and of course Mary Shelley's Frankenstein (1818). Even H.G. Wells's The Time Machine (1898) is actually a story about evolution rather than time travel. As David J. Lake has shown convincingly, Wells constructed his plot to avoid time travel paradoxes, which shows that Wells understood the logical problems inherent in time travel but he was only interested in the time machine as a vehicle to propel his narrator across evolutionary time scales.

All of these stories were remarkably accurate for their time. It still astonishes me, for instance, how well Campbell understood the principles of heredity despite writing "Who Goes There?" more than a decade before the structure of DNA was elucidated. Wells's description of the stars wheeling, nebulas flaring, and the sky changing as the narrator speeds through time still holds awesome power, and he was writing before anyone knew what galaxies were.

Superficially, evolutionary theory has been held in high esteem by the genre. However, a closer look is not so complimentary. While these authors did explore evolution and biology, their works are not remembered for what they had to say about the subject. Frankenstein has become a horror trope for characters to flee and the time machine has become a science fiction trope for characters to solve abstract puzzles. "Who Goes There?" is remembered (rarely) as the thriller that inspired Howard Hawks's The Thing From Another World and John Carpenter's The Thing. Huxley's novel is now a poster child for technophobes and is usually misrepresented. And who the hell reads Olaf Stapledon nowadays?

Each of these writers was inspired by humanity embedded in flesh, by the play of biology in our lives and the shadow evolution throws across our societies. Yet their evolutionary messages are now forgotten, and these are among the best and most influential writers in the genre.

The biological revolution of the later 20th century opened the eyes of the genre, but biology in SF tends towards killer bugs and evil mutants even today. Evolution itself, as a process, is examined only by the most scientifically aware writers in the genre such as Michael Swanwick in Bones of the Earth or Gregory Benford in the Galactic Centre novels or in Robert Charles Wilson's recent and outstanding Spin. Outside the small coterie of educated writers who are producing work for educated readers, the theory of evolution might as well not exist. When evolution is mentioned, it is usually a ridiculous caricature, such as in the infamous "Genesis" episode of Star Trek: The Next Generation in which the crew "de-evolve" because their "introns have been activated", and turn into creatures based on "dormant genetic codes held over from earlier evolutionary times." This would all be absurd enough, but the screenwriter (whom I shall mercifully leave uncredited) has some characters "de-evolve" into creatures like spiders that have never been on the same evolutionary branch as humans. There were no spiders among human ancestors, so there is no way we could be carrying ancestral spider DNA. It is hard to overstate the lameness of this scenario. In a mainstream setting, this would be like a truck driver running out of gas in the middle of the desert and getting his rig going again by filling the tank with treacle. Hydrocarbons and carbohydrates are made of the same stuff, right?

There is as much joy to be had in gnashing one's teeth at bad science as there is in praising the best, but there is little to learn about common misperceptions from either the scientifically literate or the abysmally ignorant. By and large, the most interesting errors are made by those who know just enough to make clever mistakes.

Here are a few of them.

Evolution is slow

Charles Darwin knew the Earth was old. From a careful study of geology, he estimated that our planet was at least 300 million years old and that life had existed for at least 200 million years. This was a very controversial conclusion. In Darwin's time Young Earth Creationism was still a respectable scientific belief, and although it was beginning to crumble under the weight of geological evidence, it still had many staunch and intelligent supporters. Lord Kelvin, one of the architects of thermodynamics, argued very well that the Earth could not be more than twenty million years old. His calculation was based on his field of expertise. A hot, molten Earth could not be more than twenty million years old or else it would have cooled to below freezing point. We now know that the Earth is far older than either Darwin or Kelvin estimated. Both their estimates were carefully constructed but based on limited knowledge. We now know a great deal more about geology than in Darwin's day, and we also know that the Earth's core has a hidden energy source, radioactive decay, that has kept it warmer than Kelvin could have imagined.

The Earth is around 4 billion years old, so Darwin was out by a factor of thirteen and Kelvin was out by a factor of two hundred. Even so, Darwin's 300 million years seemed like a vast expanse to a man who had once studied for the Anglican priesthood, steeped in Young Earth Creationism and its mere six thousand years of creation. So Darwin, when he imagined evolution, saw it stretching across epochs. Combined with the paucity of fossils in his time, Darwin was left with the overwhelming impression of evolution as a slow process that worked on the same scale as the rising of mountain chains.

In a limited sense, it is true. Some evolutionary processes do take geological time. It took hundreds of millions of years for photosynthetic organisms to build up enough oxygen for the atmosphere to be breathable by animals. Sharks are renowned for being relatively conservative across time. Famously, the basic anatomy of sharks has barely changed in 400 million years.

It is hardly surprising then that so many people see evolution as a glacial process. In fact it is very, very fast. The reason why sharks have not changed their body shape in 400 million years is that they have been highly efficient all that time. There is little that evolution can do to improve their anatomy. In genetic algorithm terms, the sharks reached a local maximum ninety million years ago and they have had no capacity for further improvement. But this only applies only to shark anatomy. There is a lot more to an animal than its skeleton and the shape of its flesh. While the body plan of sharks has been highly conserved, other aspects of their bodies have been evolving at a great clip, such as their immune systems and their globins. Antibodies and haemoglobin molecules do not leave fossils, so Darwin had no way of knowing how fast they evolved.

Mammals seem to be evolving six times faster than sharks. Finches in the Galapagos Islands can be seen evolving from season to season as different weather patterns favour different populations of seeds and nuts, and thence different finch beaks. All of these pale in comparison to bacteria and viruses, which evolve at a fantastic rate. When a new antibiotic is introduced, bacterial resistance is usually seen within a few years, and the rate of resistance increases with the increase in usage.

The influenza virus evolves a million times faster than humans, which is why people need an influenza vaccine every year. It isn't because our immunity wears off in a year, it's because new strains of influenza are evolving all the time and new epidemics erupt several times each year. The grand champion of evolutionary speed may be HIV, the virus responsible for AIDS. Its proteins evolve at much the same rate as influenza, but unlike influenza, HIV keeps on evolving in a single host. In fact, HIV evolves so efficiently that it becomes resistant to antiviral treatments very quickly. Most HIV-infected people need to take multiple antivirals because if they use just one, the virus soon becomes immune to that treatment.

Evolution looks slow when all you have to measure it by is fossils and skeletons. Today we can see much deeper. With gene sequencing and proteinomics, we can measure the changes in DNA and proteins that are the very essence of evolution. At the fundamental level, evolution isn't slow at all. Evolution flies.

Most mutations are harmful

Most of the mutations we see are harmful. But that is because we only take notice of disease. In fact, mutations are common, with some estimates as high as 175 mutations per human baby. And this is just at the start. At adulthood, humans contain around 50 trillion cells, many of which have descended through dozens of cell divisions. This means that each and every one of us is made up of a patchwork quilt of mutant cells.

With all these mutations going on, how is it possible to be healthy?

There are several reasons. The first is that not all mutations cause a problem. There are "neutral" mutations, where the genetic code is altered but the end-product is the same. The genetic code GCC stands for the amino acid alanine and so does GCA, so if a mutation changes GCC to GCA, then the protein in question will be completely unchanged. Imagine a typist making a mistake and typing "burned" instead of "burnt." The words are spelled differently, but they are functionally identical. The meaning is intact. This is a neutral mutation, and we now know that these are critical to the mechanism of evolution.

Even when a mutation makes a non-neutral change, it may have no effect on the organism because it hits a functionless part of the genome. There are large slabs of our DNA that serve no function at all. If a mutation changes a non-functional stretch of DNA, it will often make no difference.

Even a functional change in a working gene is usually not damaging. Most of the genes we carry in pairs. We inherit one copy from our father and one from our mother. This means that if one of the genes is disrupted, the other gene is still viable. In most cases, the spare gene will work perfectly well. There are some genes that need both copies to work, but these are in the minority.

And then, even if you get a mutation in a functional gene that requires both copies to work, the results are not always disastrous. DNA is like a string of letters that give the order of amino acids to build into a protein. If there is a mutation, sometimes the protein is still functional. It may not be as good as the normal protein, but it can still work well enough to not be noticed. There is a disease called haemochromatosis that is caused by a buildup of iron in the body. The disease is due to a mutation in a gene called HFE, which leads to the body absorbing more iron than it can cope with. Iron deposits form in the liver and other tissues, leading to cirrhosis, heart disease, and diabetes. Haemochromatosis was once thought to be a rare disease, but modern gene screening has revealed that about one in 400 people is at risk of it. The reason it has been considered so rare is that many mutations are mild enough to carry less than 1% risk of developing the disease.

Mutants are deformed

This is one of those bizarre myths that crops up a lot in science fiction. Mutants are usually not deformed. Most mutations that lead to major body defects are incompatible with life. And as we've already seen, most of us are mutants 175 times over, including supermodels. And red hair, which some people find attractive, is due to a relatively recent mutation 20,000 years ago. There is even a mutation for spangly layered hair that most researchers describe as very beautiful.

Bad genes will always be weeded out of the gene pool

It is certainly true that most bad genes will be weeded out of the gene pool, but not always. Some genes persist because they are common mutations, which means that even though they are selected against, they still crop up frequently. Cystic fibrosis, for instance, is a deadly disease that has a mean survival age of around thirty-two years. Before modern treatments, the mean age of survival was only six or seven, so nobody with cystic fibrosis lived long enough to pass on their genes until the 1960s. You would think, then, that cystic fibrosis was a rare disease. In fact cystic fibrosis affects one in 2500 babies, and a whopping one person in 25 is a carrier.

Cystic fibrosis is so common that many scientists do not believe it could be just a case of frequent new mutations. As a comparison, consider achondroplasia, the disease that causes dwarfism and Daschunds. Eighty percent of cases are new mutations. Despite the fact that achondroplasia is genetically dominant (that is, you only need one copy of the mutant gene to have the disease), only one in 10,000 people have the condition. If this non-lethal mutation is so rare, why is the terribly lethal cystic fibrosis gene so common?

One hypothesis is that the cystic fibrosis gene gives carriers a small reproductive benefit. As the gene becomes more common in the gene pool, so will matches between carriers, and this will increase the rate of cystic fibrosis. Eventually the gene frequency will reach equilibrium when the small but common benefit of having one mutant gene is matched by the rare but terrible disease from having two copies. Opinion is still divided on whether this "heterozygote advantage" applies to cystic fibrosis, and if it does, exactly what the advantage is.

But there is little doubt about albinism. In most groups, this is a rare disease: for African-Americans it affects around one in 10,000 people and in white Americans, it's around 1 in 36,000, but in Hopi and Zuni Native Americans, albinism is extraordinarily common at 1 in 200 people. Albinism is not a good trait in a hunter-gatherer society. The lack of skin pigmentation and eye complications means that going out hunting, scavenging, or even picking fruit means sunburn, skin cancer, and trouble seeing what you're doing. So why is albinism so common in these hunter-gatherer societies? One controversial hypothesis is that affected men do not go on hunting expeditions. This not only protects them from the dangers of the hunt, it means they get to stay at home with all the women...

Whether this is the right answer or not, the frequency of albinism shows that a serious disease can be exceedingly common under the right conditions. "Bad" genes can sometimes do rather well.

But wait, there's more�

This has been a brief look at some of the surprising aspects of evolution. Next time, we will dispel the myths that inbreeding is bad for the gene pool; that junk DNA has no function, and conversely that junk DNA is chock-full of hidden functions; that humans have stopped evolving; and finally, we shall see that the Tree of Life is not what you think it is.

Chris Lawson is a writer and family doctor in Melbourne, Australia.

His short fiction has been published internationally and translated in French, Czech, and Bulgarian. His first sale appeared in the respected Perth journal Eidolon. Since then he has appeared in Asimov's Science Fiction, the World Fantasy Award winning anthology Dreaming Down-Under, Spectrum SF, Event Horizon, Gathering the Bones, and Agog! His best-known stories, "Unborn Again" and "Written in Blood", have been reprinted in several Year's Best anthologies. "Written in Blood" was selected for the historical retrospective of Australian science fiction Under Centaurus (Tor, 2000). "Unborn Again" has been optioned for feature film development.

Lawson is developing a reputation for his essays and non-fiction. Snippets of these can be found on his Frankenstein Journal blog and in his first collection Written in Blood (MirrorDanse Press, 2003). His non-fiction has been published by LOCUS, Borderlands, and TiconderogaOnline, among others.

He lives with his wife and two children. He only speaks of himself in the third person on occasions.

Counter-Intuitive: Still Evolving After All These Years