Hey guys, Jonathan12345 here at Chapterhouse again with some good-old fashioned biomed.
If you’ve paid any attention to medicine in the recent years, you may have have heard of ‘superbugs’. These bacteria are resistant to many common antibiotics. If you’ve ever dug a bit deeper, you might’ve even heard that bacteria have evolved themselves to be resistant to antibiotics.
This is complete bullshit. Let me explain why.
It’s true that many strains of bacteria have resistance to common antibiotics now. However, they didn’t consciously choose to evolve resistance–that’s not how evolution works. As an example, could you suddenly evolve the ability to fly? I thought so.
The truth behind what happens is that bacteria reproduce so quickly, they accumulate many random mutations fast, some of which are bound to cause resistance to antibiotics. When these antibiotics are used, the bacteria that can’t survive die, while the ones with resistance survive and grow more common. This process, natural selection, we touched on in my previous article about evolution.
The idea, now discredited, that beings could choose to evolve, was first proposed by Jean-Baptiste Lamarck. Now, while we know that his ideas are garbage today, we can’t completed discredit him as he lived before Darwin, and still managed to propose a (albeit flawed) theory of evolution.
What Lamarck believed was that animals had an innate desire to become perfect. They would try very hard to get the traits they desired (how they did this was never touched upon), and pass these improved traits to their offspring. Needless to say, this idea is stupid. If you lose an arm to a flying knife, does that mean your children will also be missing an arm? No.
The advent of genetics sealed the fate of Lamarckism. There is simply no way to modify your own genes without relying on tools, so there was no pathway left where Lamarckism would still be feasible.
Despite the evidence to the contrary, Lamarckism has survived amid the populace because of its straightforwardness. Just remember that you can never consciously “choose to evolve.”
That’s all for Chapterhouse today, and as always I’ll see you in the next one.
While Lamarckian evolution is categorically incorrect for genetics, is somewhat accurate for the field of epigenetics. While genetics studies your genes, epigenetics studies how those genes are expressed, “turned up or turned down” using various chemical markers on the DNA.
For example, each cell in your body has all the DNA to become any other cell in the body (pluripotency). This is how one fertilized egg can divide into the myriad cells of your body. How come your skin cells don’t turn into neurons after you’re fully grown? Epigenetics. As your cells specialize into the various functions of the body, they disable the genes they don’t need via a variety of chemical markers. So your skin cells will disable the genes for neurons, heart, stomach, etc.
Epigenetics is also at fault for cancer. When you are a fertilized egg, your body needs to divide and grow as quickly as possible. The genes that up-regulate the division rate are turned on at first. Once you are finished growing, said genes are disabled. However, cancers arise when the chemical markers that disable those genes are damaged, accidentally turning up growth speed. For example, when you smoke a cigarette, not only can the cigarette smoke mutate the genes in your lungs, they can also damage the epigenetic markers (epigenome) in your lung cells. Both can lead to lung cancer.
Epigenetics play the key role in the nurture side of the nature-nurture dichotomy. For example, epigenetics helps regulate your metabolism (how fast you burn calories). If someone gets very little food for much of their life (like in much of the developing world), their epigenome will change, instructing cells to burn less calories and conserve energy. However, if you suddenly give this same person tons of calories (like developing countries with fast food), their body will initially be unable to keep up with the influx, as their epigenome is still designed for a low-calorie environment. This is partially the reason why developing countries tend to have dramatic increases in obesity and diabetes as food availability increases.
Your epigenome can even be passed on to your kids via epigenetic markers on egg and sperm DNA. Using our previous example, properties of your parents’ metabolism can be passed onto you via their epigenome, affecting your own likelihood of obesity and diabetes. In this way the environment, not just the genes, of your ancestors affects you and your descendants.
Not all hope is lost however! In the same way the environment of your ancestors changed their epigenomes, your own environment and behavior can change your epigenome too. As an example, if you eat healthy with good nutrition, over time it can change your epigenome for the better, and you can pass these improvements to your descendants. In this way Lamarckian evolution is still kinda true!
If you want to learn more, here is a great list of introductory resources:
Why the downvote? This stuff is taught in undergrad-level biology and is pretty established science.
I know there have been a number of pseudoscience peddlers who say you can use ‘mind control’ to improve your epigenome and health. That is complete bullshit. You can’t improve your epigenome health just by thinking about it. You have to physically change your environment and behaviors to make a difference. For example, you can’t change your metabolism just by thinking about it, you have to change what you eat and how you eat so that your epigenome can respond.
I’m open to answering any questions y’all have on epigenetics.