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Paywall free archive: https://archive.ph/xCfBT
Expanding on this, CGP Grey had this amazing video (https://www.youtube.com/watch?v=JEYh5WACqEk) of why European diseases in the Americas were so bad on the people that were already here when the two worlds met but you hardly heard of Europeans getting any super contagious illness from the people living in the Americas. Meaning European genomes had some adaptations (as well as antibodies?) from dense and unsanitary living, as well as animal farming in European prior to contact whereas that type of living setup was rarer in the Americas.
Apparently native populations had a different immunogenic profile and that made them more susceptible to European diseases such as smallpox, and this was amplified by the lack of any immunity acquired by childhood exposures:
https://psmag.com/news/how-native-american-genes-tell-the-st...
Charles C. Mann has a whole chapter on the epidemics that ravaged the Americas after the European arrival, in "1491: New Revelations of the Americas Before Colombus (2005)", and discusses this and other theories.
It's been discussed in many places on the internet before, but CGP Grey has a lot of profound misunderstandings around the Columbian Exchange and the new world as a whole. Some of it is that he's not an expert, some of it is that he chose particularly bad sources (e.g. the zoonotic hypothesis he cribbed almost directly from one of Diamond's older papers), and some of it is that there's a lot of misinformation about this particular topic on the internet.
The reality is that dense urban settlements (many without good hygiene), domestic animals (e.g. parrots), unsanitary conditions, and widespread trade/social networks all existed, subject to the usual caveats of time and place. We even have strong evidence of highly contagious diseases like Kirsten Bos' paper on zoonotic Tuberculosis in ancient Peru.
There are still many open questions regarding why the Columbian Exchange happened the way it did. Academics are still trying to work out the truth through centuries of mistaken narratives about what went down, including the now-suspect idea that there was ever a single continent-wide epidemic wave. We can reject some ideas (like innate genetic susceptibility) on the basis of scanty evidence, but most of them are hard to definitively reject and few people have the knowledge base to write books challenging the dunning-kruger type academics that are comfortable talking about continent-wide phenomena with simple narratives.
Covid made the social dynamics of epidemics a particularly interesting research topic to grad students, so maybe there'll be more consensus about big questions in a few years.
>It's been discussed in many places on the internet before, but CGP Grey has a lot of profound misunderstandings around
It is not just CGP Grey; other popular channels also share tons of misunderstandings and stuff related to tech or science. I believe YouTube also favours popular channels because of the high likes and comments. They dominate both Google and YouTube searches. I started noticing this around topics like Firewalls, RPis, Linux, Coastal Erosion, Global Warming, open source etc. The reason why top YouTubers are popular is because of their presentation style. It would be best if you did your research using multiple sources. Ask a question to university professors on Twitter (or email them), and they will happily guide you to the right resources. At least, that is how I do it and it worked better for me. YMMV.
Yeah I love some of these pop historical/sociological youtubers - until they venture into one of the tiny domains I know a little about, and I listen to their misunderstandings.
Then of course I think about how likely their knowledge of other topics - on which I "trusted" them due to my own ignorance - is similarly surface level.
On the topic of Linux:
To properly install Arch Linux (The way I want it setup) on my machine without any hitches, I need to use like.. 7 different videos, because they each leave something out that the other included.
Yes, yes, I know I should/could just use the Arch wiki. I really should just go do a deep dive into it someday. But my method works, so why fix it?
You're correct that some cities existed in the Americas on par or larger than most European cities (ie Teotihuacan). I don't know why people don't just chalk it up to an accident of viral/biological disease evolution. You could imagine an alternate timeline where the native Americans had survived similarly horrific incidents as the Justinian and Black Plagues, as well as Smallpox, but then Colombian exchange brought back the diseases to Europe.
Maybe it was just an unfortunate coin flip of history.
Maybe the racial diversity in the Eurasian-African land mass contributed to the disease diversity and acuity?
If you just want my idle speculation, my personal guess is that diseases did exist in the Americas, but 1) we lack the ability to see them in the record and 2) the dynamics of how those diseases originated/spread is significantly different between afroeurasia and the new world.
One of the problems with archaeology is that things have to be archeologically visible in order for us to realize they exist. Diseases usually don't leave skeletal evidence and many American cultures were big on cremation besides. It's only under very unique circumstances with certain diseases (e.g. the mummies with tuberculosis mentioned previously) that we can clearly see the evidence to say "hey, these people died in a disease outbreak". In Eurasia we rely heavily on literary sources to supplement this issue, but we have few American sources and they're mostly focused on other things.
The nature of continents is also substantially different. The Americas were hugely affected by late quaternary extinctions that destroyed the mammalian diversity, a main factor in zoonotic transmission [1]. The places where that diversity exists post-LGM like the Amazon basin are very remote and their pre-Columbian history is not well studied, let alone the history of disease there. We have little understanding of how they integrated into broader American trade networks either. Eurasia's biodiversity is spread across large areas of the continent, which happen to be crossed by continental trade routes. If plague had originated in Venezuela instead of from rodents in central Asia, we might not even know about historical outbreaks and simply label it a new disease when modern farmers in the highlands caught it.
According to Wikipedia, Teotihuacan had an estimated population of 125,000 or more, "making it at least the sixth-largest city in the world during its epoch at its zenith", which is thought to be no later than 550 CE. Rome is estimated to have had 1,000,000 inhabitants around 0 CE. Certainly the Europeans had much greater population and density. How could they not be carrying around more virulent parasites?
> We can reject some ideas (like innate genetic susceptibility) on the basis of scanty evidence
This is an article about genetic selection due to the plague in Europe. Lol.
The idea I'm talking about here is an older one that virgin soil epidemics devastated American populations because they were innately susceptible to them, often as a result of genetic homogeneity or something. That's not supported by decades of research into those kinds of questions.
This article is talking about selective pressure as a result of epidemics, which is absolutely a thing.
Interesting!
But wouldn’t a tb outbreak in ancient Peru line up with what cgp grey is saying, in that they had close contact with Llamas?
The tuberculosis came from pacific seals, so no. I wouldn't put it past the llamas to have planned it though.
Syphilis is a disease thought to have come from the Americas to the Old World.
One thing that will be interesting to watch is the long term effect of modern medicine. You can't believe in darwin and think that relieving the selective pressure will have no consequences. By saving kids that merciless nature would have naturally killed, I think we are also "breeding" a human species that is inadapted to its environment, fragile. And I wonder if the high level of allergies seen in kids today isn't an early symptom of that.
Humans have a long history of relegating certain bodily functions to technology outside their bodies, to lower the requirements for survival.
Frying meat lowered requirements for the intestine, the immune system, and the teeth, compared to eating raw meat.
Baking bread lowered these requirements even further: old people who lost almost all teeth could now survive and be useful.
Various medical inventions saved innumerable lives, including some people who would otherwise die young, bur who lived enough to make a large impact on culture.
Probably this process will continue, producing a more fragile general population with more impressive outliers, and maybe even more (intellectually or otherwise) impressive baseline.
Genetic diversity is the way to go for resiliency.
If a species lives under constant, high selective pressure, it becomes highly adapted for the current environment. If the current environment changes a little -- too hot, too cold, more rain, less rain, a new disease evolves -- then the entire species becomes unfit for its new environment, and it may not survive long enough for new mutations to arise that happen to be better suited to the new environment.
If a species lives under weak selective pressure, it will only be weakly adapted to its current environment ... but it is much more likely that some part of it will be varied in a way that protects it or advantages it in the face of a changing environment. If selection pressure becomes harder -- if shit hits the fan -- it may be bad for a large chunk of the population, but it is more likely that at least some part of it will survive.
Take potatoes -- you fill a field full of genetically identical potatoes which are perfectly suited to the climate and conditions you're growing in, and you can get just monstrous yields. But if the slightest thing goes wrong, if a new blight takes hold, the entire crop can be lost to the last. The population is strong, but fragile.
And that is why eugenics is just so, so dumb, in addition to being, you know, ethically wrong.
Isn't that what has been happening since humans have existed? We have to wear clothes to live in most environments for instance, that is a good sign of not being naturally adapted.
> ... that is inadapted to its environment, fragile.
No. The "environment" of modern humans now includes modern medicine. Of course, if this aspect of the "environment" changes after awhile again, they would be more fragile than the current population in this respect on average. But the same is true for any (ancient) population confronted with new contexts. There is no fundamental difference between man-made environmental changes and natural ones.
As this article shows, with evolution it is hit-or-miss whether the response to a pathogen has collateral damage. In medicine, we can be more proactive about it.
Humanity isn't going to develop a widespread genetic resistance to TB in the near future that wipes out TB if we just let tons of people die from it. The idea that we are breeding weakness into society by using medicine and that we'd have a superior society by denying medicine to people is both medically wrong and frankly disgusting.
However, with modern high density cities and long distance travel, people are subjected to a much greater number of diseases than in pre-industrial times.
Humanity isn't going to develop a genetic resistance to TB in the near future if we just let tons of people die from it. The idea that we are breeding weakness into society by using medicine and that we'd have a superior society by denying medicine to people is both medically wrong and frankly disgusting.
The science is fascinating, the conclusions compelling, but why didn't these mutations appear during Justinian's Plague?[1] And if mutations helping resistance to plague were already present from 550AD, why was the Black Plague so devastating 800 years later? 800 years is plenty of time for the mutations to have spread to all of Europe, and yet Black Plague killed as much as 60% of the total European population.
Are we sure that no mutations exist from the Justinian? How genetically similar were the bacteria that caused the two plagues?
One theory off the top of my head, maybe Justinian affected elderly but not the young as much? If true, there would be little selective pressure applied.
> How genetically similar were the bacteria that caused the two plagues?
Genetic similarity is far too specific, but both plagues were caused by the same organism and bacteria species, Yersinia pestis.
Covid killed a lot of people even though we have at least four other coronaviruses running around causing common cold, and most of the victims had some banal coronavirus infection before.
The plague bacteria of 550 AD was probably not completely identical to the one in 1350 AD either.
> The plague bacteria of 550 AD was probably not completely identical to the one in 1350 AD either.
Both plagues were caused by the same bacteria, Yersinia pestis. I don't see how being "completely identical" would matter, only that it was the same species of bacteria.
Covid killed a lot "old people", people well past reproductive age.
800 years is also a lot of time for genetic drift to occur. If it’s not being actively selected for anymore, it can end up being in increasingly smaller parts of the population.
Genetic drift occurs due to random chance, unlike natural selection. Presumably, the population that survived Justinian's Plague had beneficial mutations. While it is possible that 40 generations is long enough for genetic drift as populations mix and become heterogeneous, the surviving population was homogeneous in regards to those beneficial mutations. The bacterium Yersinia pestis never actually went away, so plague deaths continued uninterrupted during those 800 years, just not at the level of pandemic. Those mutations would continue to be beneficial and those with them continued to be actively selected for survival.
Thanks for putting it as 800 years. In fact, we are closer to the black death now than they were to the justinian plague. Just a small thing that was interesting to notice.
'Survival of the Sickest' by Sharon Moalem covers this and several other diseases that are related to survival at a cost as well. Fun read for the interested!
https://en.wikipedia.org/wiki/Survival_of_the_Sickest_(book)
This ties in nicely with the Crohn's cold-chain hypothesis.
https://pubmed.ncbi.nlm.nih.gov/32949122/
It gives me hope that maybe one day we can figure some of these autoimmune issues out.
I have very weird food autoimmune issues (sinus headaches from a lot of common stuff). Often when I say something about gluten people will bring up the relatively recent increase in intolerances. Some will point to genetically engineered crops, some to the use of glyphosate. I always thought maybe we had more variety and more awareness now (i.e. 1000 years ago my options would have been limited and I'd just suffer, now I have choice).
I saw this same article on NPR a few days ago and it is really cool that it might be a genetic adaptation. I almost never get sick (besides from food) so an overactive immune system would make sense.
There is also (sometimes contested) academic research about adherence to a gluten free diet having positive health outcomes for autism, schizophrenia, and bipolar disorder. The mechanism, as I've seen it explained, is that autistic people's bodies treat gluten / casein as an opiate (exorphine is the word they use) which mirrors my experience with sinus headaches (it feels like a withdrawal).
Wandering post to say this research is super exciting and there is a ton of crazy stuff around food.
If you factor in that we ran around with ringworms that emit immunosuppresants to protect themselves...
Various similar examples of this: https://en.wikipedia.org/wiki/Heterozygote_advantage
I wonder if the same thing will happen with COVID.
The article literally says it's probably not going to happen.
> He said that it was unlikely that Covid-19 outbreak would shape our immune system in a similar way — largely because the disease predominantly kills people after their reproductive age, meaning it's unlikely genes that confer protection would be passed on to the next generation.
This article states that Covid-19 is the seventh leading cause of death in the US between the ages of 0 and 19 years old, based on data between 2020 and 2022: https://www.news-medical.net/news/20220527/COVID-19-found-to...
This CDC presentation focuses on more recent data and places it at 4th or 5th leading cause of death in the US within those age ranges, based on finer age brackets: https://www.cdc.gov/vaccines/acip/meetings/downloads/slides-...
Looks like selective pressure to me.
What about long covid?
Covid kills old people, the disease needs to kill young people, before they have kids, to have an impact on the gene pool (unless other factors than Darwinism are at play in the evolution of genes).
archive is a godsend. so many paywalls
We detached this comment from https://news.ycombinator.com/item?id=33294533.
> made people 40 percent likelier to survive the Black Death
Didn't know likelier is a word that exists in English.
Also please for the love of god, support dark mode.
Check out Dark Reader addon. https://darkreader.org/ Works in pretty much all browsers. On FF for Android it can even follow system settings for Dark Mode and for me only turn on between 20 and 6 o'clock.
I use brave on mobile which doesn't support extensions.
There is built-in chromium dark mode, which seems OK but its not possible to disable it per tab.
Firefox on android for me is pretty slow.