Seems like a contradiction to me. If we are saying the majority of humans are incredibly genetically similar except for some genes that code for pigmentation but also there are reduced clinical efficacy for drugs based on certain races. I can understand outliers like sickle cell anemia but this diversity of sampling is required for every drug.
When they do clinical testing, pharma companies try to pull from different racial groups to ensure their drug works across demographics. If we were that genetically similar then wouldn’t pulling from one group primarily do the job?
Please don’t make this a white supermacist thing. I don’t believe in that stuff. Legitimately just curious.
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They want to be very very thorough. If even a tiny tiny genetic difference can have an impact on how effective the medicine is, they want to be certain it works. Yes, the genetic differences between humans is relatively minor, mostly surface level, but there are enough tiny quirks that it’s worth being thorough when doing clinical exams.
Pulling from different racial groups is a convenient/easy proxy for “pull from a wide variety of genetic backgrounds so you don’t miss something.”
There’s nothing magic about the skin pigmentation genes, there’s no causation, but there *is* correlation between different genetic backgrounds. For example, you’re much more likely to be lactose intolerant (which might be relevant to some medicine formulations) if your genetic heritage is rooted in Asia. This does *not* mean that lactose intolerance is carried on the same genes as epicanthic folds (“Asian eyes”) or that particular skin pigmentation, it’s not, but saying “make sure you’ve got a representative sample of Asians in your test sample” makes it way more likely you’ll pick up lactose intolerance and is far simpler to actually do than “test everyone in your sample through ancestry.com to make sure you’ve got a representative genetic spread”. Similar logic applies to a ton of genetic pre-dispositions.
It’s not just race…you want to make sure you’ve got a wide spread of sexes for the same reason. Men & women are only different by a single chromosome but that has *huge* biological implications.
Instead of thinking about the human genetics, think about it in terms of cannabis. If you take a single strain and provide it to multiple people, you’re going to get multiple side effects reported. Tired, dizzy, munchies, paranoia, etc. It comes down to how your body processes the different cannabinoids and compounds within the trichomes.Now take that to something that has side effects that are potentially hazardous (bleeding, allergic reactions, etc). As a clinician you will want to know what causes that side effect, and how different changes in physiology play a roll.People with higher metabolism for example would process a time released agent faster than someone with a slower metabolism.Possibly they’re looking at glaucoma and how the genetic differences that cause eye colour also effects how the patient’s glaucoma progresses.
A side note: This is also one of the reasons that a medical professional may ask your gender at birth. Regardless of gender assignment, a “genetically female” body has differing hormones and chemicals then a “genetically male” body. Creatine values in the body, for example, play a major roll in cancer treatment. Male and female patients need different dose calculations because of their different CrCl (creatine clearance) values, BSA, BMI, etc. If you’re a trans male (F to M) and inform the doctor that you’re genetically male, the dose that you’re given could kill you.
Because drug metabolism is one of the few things in life that really can hinge on one or two genes. It’s still usually irrelevant (e.g. race-based Tylenol dosing guidelines would look something like “who gives a shit what color you are, take some if it helps but no more than 3 grams daily) but there’s just enough potential risk that it’s worth looking into. Certain minor genetic variants that wouldn’t matter otherwise can really affect medication, and are concentrated in certain populations. Drawing from multiple racial groups can be a fair enough proxy for a genetically diverse sample, although you have to be thoughtful about what the groups actually represent.
For instance, carbamazepine is an anticonvulsant with a very finicky metabolism and potential to cause a serious rash if your immune system takes a dislike to it. A certain variant of one of the things our white blood cells use to figure out friend vs. foe leads to a much higher rash risk, and it happens to be much more common in people whose recent ancestors are from east Asia.
Sometimes it’s as simple as dosing. A colleague once told us about needing to alter the typical amount and frequency of TB medication when working on a Navajo reservation, as many of the locals metabolized the drug in question much more quickly than the average European. Again, this isn’t something that would otherwise matter in life, but affects whether it’s dosed once a day or twice a day.
While genetic differences between races is small (in fact, the genetic differences between any two people on Earth of the same biological sex is at most something stupidly small like 0.02%) different races can have different frequencies of alleles (gene variations).
Those same alleles will be found in other races but they will be more of less common in different races. This may change how different medications react in different races statistically but not necessarily individually.
It’s not really a contradiction — when the “incredibly genetically similar” argument is used in an anti-racist context it basically just means that no race is inherently more-or-less-human than the other. The human race as a whole is still significantly more genetically distinct from our closest (ape) relative, than we are from each other. It doesn’t tell you anything about what happens when you pop an extra-strength Tylenol — to that end me & my dad are super close genetically but probably still don’t experience the same effect, down to differences like body mass, age etc.
There can be a vast difference between a person’s genotype (fancy word for “what do the genes say”) and their phenotype (what we actually see manifested in real life). This is mostly to do with dominant vs recessive genes — a recessive gene doesn’t express itself in the phenotype unless you receive a copy of it from both your parents (otherwise a dominant gene will override a recessive one).
Bit of a side note, but this is also why inbreeding is generally considered harmful, as it increases the likelihood of the child inheriting the same recessive gene from both parents. Recessive genes aren’t necessarily *bad*, but they could be — and you might not even know you’re carrying a harmful recessive gene if it’s never manifested in your family before (until someone was unfortunate enough to get a double serving). See wikipedia’s [introduction to genetics](https://en.wikipedia.org/wiki/Introduction_to_genetics) for a further (roughly ELI5’d) explanation.
Humans have tens or hundreds of thousands of genes (the exact numbers are still [hotly debated](https://bmcbiol.biomedcentral.com/articles/10.1186/s12915-018-0564-x)), and even one gene being missing or present can lead to a vastly different outcome. You mentioned sickle cell anemia, someone else mentioned lactose intolerance — these are all good examples. Now imagine that we don’t fully understand how all the genes work, **and** we’ve created a fresh new substance that humans have never ingested before. You’re going to want some heavy duty testing until you’re reasonably confident that your product is safe for everyone, if the expression of even a single gene could spell disaster.
Like someone else said, racial group based testing is likely more of a shorthand for “this person is coming a previously geographically isolated community (i.e. a different continent), so they’re likely to have *relevant* genetic variety compared to other groups”.
(disclaimer: I’m not a geneticist or anything, but I really liked this topic back in high school biology)
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