Creepy Mendelianism!

I dug into one of my YouTube comments and regretted the failure of teaching genetics. We must stay away from Mendel! It’s not about the individual, his ideas about genetics, primitive (but useful!), are now outdated.

Transcript below the fold.

I am in slow motion mode today. I am taking medication for my back pain! Still, I think I have enough brains to deal with Jordan Peterson fans. So I found this comment in last week’s video and thought it was easy to handle, even with half my brain tied behind my back, or whatever inappropriate phrase Kent Hovind used.

The problem is that I attack Jordan Peterson for the stupid idea that if he takes the right kind of drug, he can turn his brain into a microscope and see DNA molecules. He did not provide any evidence that he could do this. I guess he needs to know that the truth doesn’t care how you feel.

I get a wave of stupid traffic because of this: people who log in tell me that drugs are great, I don’t understand the metaconcept Peterson is discussing, call me stupid, I miss the context behind his claims, etc. They’re trying to rationalize Peterson’s alleged patent idiots. I’m so sorry for them!

Of course, one of the more common arguments is a personal attack – surprisingly, I know what that means, unlike most people throwing Latin all over the place. This doesn’t mean insulting someone. This means using different, unrelated parts of my personality to refute my thoughts on the subject at hand. Here’s an example of someone declaring that because I’m a so-called social justice warrior, they can ignore what I’m saying about Peterson’s magical DNA eye. they said,

I won’t talk too much about Peterson, but here’s my question. PZ Myers is supposed to be a scientist, but he’s letting unscientific social justice seep in.

There is a remarkable assertion: Science, or capital-S science, has nothing to do with social justice. Actually, if the condition has empirical, measurable consequences, it can, so it’s kind of ridiculous. Even if not, scientists are human beings, and we can care whether other people are being treated fairly. This is not the objection he thinks it is. But he still told me he was a good guy!

I’m helping a trans guy overseas, helping him feed and fix his bike, so it’s not about hate or anything, but pronouns and polygender against scientific data.

Oh. The “I have a black friend” argument.

Glad they helped a trans person, but now I’m confused. You used the pronoun “he”, so are they trans people, or are you misunderstanding trans women? I’m asking because you say pronouns go against scientific data, then you can use pronouns like non-scientists. Or a normal person.

They continued to dig their holes.

This is more a matter of the mind itself, and social justice should not be confused with science.

So shouldn’t Capital-S scientists study minds or societies? Peterson is a psychologist, maybe you should go talk to him about how he can claim to be a scientist (btw, I agree, but a psychologist can be a legitimate scientist, you know). There is a whole category called social sciences which includes psychology and sociology. Who are you to define what is or is not?

Let’s summarize.

That’s why I’m not happy, because if you’re a scientist, you shouldn’t have anything to do with something that isn’t science at all, it’s more like pseudoscience than real real science.

Disappointed with you PZ, I thought you would be better than that.

It’s really shameful, and I think it’s worse than what Peterson did.

Ok, this is what I find annoying, I see a lot in the comments, especially when I talk about trans issues. The stupidest, most ignorant people show up and tell me I don’t know science, they know science better than I do. All they really know are bits and pieces of little-known genetics that they recite to support their prior biases. They also ignore the political or sociological infusion of pseudoscience they agree, and characters he likes, like Peterson, would ramble on.

Paradoxically, he finds social justice scientists more repulsive than crazy, befuddled eccentrics who preach hatred and bigotry.

But I’m trying to figure out why he thinks “scientific data” is against pronouns or more complex views of sex. I think I know how they came to this conclusion, which is a common problem in genetics education. Early genetics instruction in public schools often started and ended with Mendel, making students think of genetics as relatively simple and deterministic. I suspect many listeners of this video think they know the basics of genetics: there are dominant and recessive genes, they are sorted and recombined in meiosis and fertilization, and which you express is a binary decision. The classic story of the Y chromosome fits perfectly with this simple idea: Y is a male chromosome, if you inherit one, you’re male, if you don’t get one, you’re female, and that’s it.

That’s the problem. Mendel’s work is an initial insight into a possible mechanism. His results from pea plants are very useful and interesting, and once they are rediscovered, promises a way to analyze heredity using mathematics, probability theory and statistics. But if you stop at Mendel, you miss all the interesting complications that come later, and you get a primitive and rigid notion of how inheritance works.

I’ve always called it creeping Mendelianism, the idea that some experiments with pea plants have crept into the public consciousness and dominated. I’m not the only one noticing! Here’s a paper published a few years ago that said the same thing:

21st century biology rejects genetic determinism, but exaggerating the role of genes in the formation of bodies and minds remains a problem. What causes this tenacity? This paper reports an exploratory study showing that a general reliance on Mendelian examples and concepts at the beginning of basic genetics teaching is a dissolvable source of support for determinism. Undergraduates who took a standard “Mendelian approach” university introductory course on genetics did not, on average, change their deterministic view of genes. In contrast, students taking the alternative course, inspired by the work of the early Mendelian critic WFR Weldon (1860-1906), replaced the emphasis on Mendelian peas with an emphasis on developmental context and its role in causing phenotypic variation. The emphasis is less on genetic determinism at the end of teaching. Both the new Weldonian curriculum and the study design will be improved in the future.

This does not mean that Mendel was completely wrong! Mendel defined a simple starting point, but advances in genetics have since overshadowed his initial ideas. I suspect most of you want to know that your education is outdated. So let me review what Mendelianism says in its most basic form.

Mendel worked backwards and deduced the existence of what he called unit factors in gametes. So an organism has a set of characteristics, which I illustrate with some colored entities; in Mendel’s case, he identified a set of characteristics of a pea plant, such as the color of a seed or flower, or the height of the plant, or other characteristic. He then does a set of carefully defined crosses, followed by careful calculations of the progeny, to correctly infer that each plant has pairs of alleles for each trait, and that some alleles are dominant (that is, the total is expressed) or recessive (i.e. not expressed if a dominant allele is present), and they are distributed randomly to offspring.

Does this sound familiar? it should. You probably learned this in a basic biology class when you were about 12 years old. One thing you may have learned beyond Mendel’s knowledge is that these genes are encoded in a molecule called DNA.

Unfortunately, you may also already understand that there is a one-to-one correspondence between genes and traits. That’s the problem. When your education stops at that point, you start thinking about “genes for X,” where X is cancer, obesity, eye color, or sexual preference. That means you don’t know all the cool stuff that comes out later.

There is no one-to-one correspondence. Each gene has multiple phenotypic traits, a phenomenon known as pleiotropy, each phenotypic trait is established by multiple genes, and they are polygenic. People are now talking about the concept of whole genes, or that each gene contributes to each trait. This means that the idea that genes serve a specific purpose mostly doesn’t work.

Another example: You can’t say the Y chromosome makes you male. The Y chromosome has a strong role in turning on and off genes in the autosomes, and even the X chromosome, which is essential for male development.

The molecular biology revolution of the 1950s also taught us that DNA is transcribed into RNA, which is exported into the cytoplasm. In addition, most but not all RNA is translated into protein. This is the only way genes can function, by sending out molecular agents in the form of RNA and proteins to do the actual work of the cell.

To further disrupt those good linear gene-to-phenotype arrows, the cytoplasm is the simmering pot of interactions and activity. Proteins communicate with other proteins and change their activity, and feedback to regulate gene expression. They also regulate themselves through feedback and feedforward mechanisms. You simply cannot draw a straight line from a gene to its effect on a phenotype! There are always side effects. It could also be that the mutational signature that the geneticists noticed was one of the secondary effects of this gene, and there was a more important primary effect that we just didn’t notice.

Finally, there is the huge influence of the environment, a parameter Mendel didn’t even take into account. The expression of genes is influenced by environmental factors, and our biology also feeds back and changes the environment.

This means that genes do not determine fate in any simple way. Every phenomenon, such as cardiovascular disease in the figure, is the product of a causal network, of which genetics is an important part, but not the only part. Mendel intentionally performed a thorough experimental reductionism, eliminating all variables that could have influenced his results, not the ones he chose to test, which is good practice in controlled experiments, but it is also artificial. exaggerates the effect of that variable.

That’s how I ended up with a group of commenters who could insist that they knew more about science than I did – their first and simplest knowledge of genetics had instilled in them an absolute moral certainty that Genes are deterministic, and anyone who talks about the importance of complexity and subtlety and other factors must be a bad scientist. They turned everything upside down!

Anyway, now you know where I’m from. Maybe you also understand better why people claiming genetic differences can lead to differences between genders, races, and countries. They have a cartoon version of genetics in their heads.

Leave a Comment

%d bloggers like this: