Book Review: A Discovery of Witches — Evolution and genetic mutations
Let’s talk about mutations. You are more familiar with the concept than you think. Take for example, the popular movie series X-Men, where the world is surprisingly full of “mutants” with extraordinary abilities, such as Wolverine, Magneto, and Storm to name a few.
I wanted to talk about evolution and genetic changes because I came across a novel that discussed it. A Discovery of Witches (2011), a New York Times bestseller and book one of the All Souls Trilogy, by historian & novelist Dr. Deborah Harkness is a drooling 4-in-1 treat for someone like myself who equally love sci-fi, fantasy, romance, and historical work. Through seamless references to alchemy, Darwinian evolution, genomic studies, and history spanning over a thousand years, the story slowly unfolds mystery surrounding the world where humans unknowingly co-exist with daemons, witches, and vampires. (And yes, the leading vampire is irresistibly attractive AND he happens to be a biochemist like myself.)
Everything seemed fine until I came across the following set of phrases, which raised my eyebrow:
“Species change, adapting to new circumstances… The instinct to survive…is a powerful one – certainly powerful enough to cause genetic changes.” (p.472, Penguin Books)
“…she might have been led to you by the pressures of survival.” (p.473, Penguin Books)
I don’t want to spoil the story for those who have yet to read the book, so suffice it to say that these phrases are referring to an individual, last in the line of a long lineage, which would have gone extinct has she not produced children. Without her knowledge of the extinction, however, her genetic make-up revealed unlikely traits, which led the scientists to conclude that the pressure to survive led to this particular genetic pattern and her behavior.
I thought that this take on the selective pressure and mutations is a bit misleading. Survival through mutations does not happen at an individual scale but rather occur over a population over multiple generations.
Here is a classic example of evolution and natural selection:
About 200 years ago in England, the majority of the peppered moths were white with speckles – just as their name suggests –, which provided them with nice camouflage against lichen-covered trees. Occasionally, some moths were born with mutations that made them black, but these were easily spotted by predators and died off. Then came the Industrial Revolution, ruthlessly pumping pollution into the air. Lichens died and trees were covered in soot, turning the once pale trees into black. White peppered moths were doomed. Predators could now easily spot the white moths against black trees. Mutant black moths, on the other hand, were now less likely to be detected and began to flourish, slowly replacing the white moth population. Much later, in the recent years, when the pollution in the air lessened and the lichens once again covered the trees, black moths were once again subject to predation. The small surviving population of white moths started to recover.
Some points from the above example:
1) This particular process of natural selection took place over the course of 200 years.
2) When the trees turned dark, threatening the white moths, this “pressure of survival” did not cause the white moths to turn black. Mutant black moths that happened to hatch during the hardship of white counterparts simply survived better than the latter.
3) If there were only a single white moth left in the world, the pressure of survival would help little. The moth cannot spontaneously change its or progeny’s genetic make-up to match what is required for survival.
4) A few mutations causing the color to change, as in the case above, is a relatively simple process compared to more drastic changes, like a human turning into a magnet, for example, that would (theoretically speaking) require dozens of mutations.
This brings me back to X-Men. Most genetic mutations are either seemingly harmless (i.e. “silent”) or deleterious, causing various genetic diseases. Just think about how miraculously fine-tuned we are to the current environment as a result of millions of years of adaptation. Mutations through either environmental cause (like nasty carcinogenic substances) or genetic recombination are unlikely to make sudden improvements. So, it is very unlikely to have a mutant like Wolverine with his conveniently retractable and deadly bones appearing in just a generation.
To add to the argument, Dr. Joseph Thornton recently gave a seminar on how mutations that happen over the course of evolution that allow the gain of new function are rare (the University of British Columbia, November 2012). Dr. Thornton is a leading scientist in the field of resurrecting ancient proteins and the mechanisms of evolution, whose work has been featured in Nature News. According to his findings, a protein evolving to have a new function comprises of a number of mutations whose combinations are extremely intricate. The wrong sequence of the combination either keeps the function of the protein unchanged or leads to malfunction. So, evolving into something new and functional (and perhaps even superior) is a long process of trial and error.
I hope you are reading the post till the end – if so, thank you for coming this far! – because I don’t want you to leave, thinking that the book A Discovery of Witches is flawed. On the contrary, I relished the story and the characters in it. The details given on the wide range of subject matters were impressive – historical manuscripts, alchemy, genetics, rowing and yoga, horseback riding, etc. – and definitely added colors to the story. I also enjoyed elements of food writing, where lush descriptions of flavors of wine appeared on multiple occasions (which is not surprising given the author’s passion for wine). I cannot wait till I get my hands on the book two of the All Souls Trilogy, Shadow of Night (which is another New York Times bestseller), and most definitely cannot wait till the third book comes out. I am also sincerely looking forward to the movie adaption of the book (which seems to be underway).
Lastly, if you’d like to dig further into the topic of genetics and evolution from the ease of your home, for free, and without prior knowledge requirement, this might be useful: Dr. Mohamed Noor from Duke University is offering a free online course titled Introduction to Genetics and Evolution starting January 4th, 2013. You can look into the details here.