13 ms·

How the ‘black death’ left its genetic mark on future generations

76 points by Petiver 4y ago

ttouch 4y ago
Paywall free archive: https://archive.ph/xCfBT https://archive.ph/xCfBT
bigmattystyles 4y ago
Expanding on this, CGP Grey had this amazing video (https://www.youtube.com/watch?v=JEYh5WACqEk 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.
- AlotOfReading 4y ago
  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.
  - bigmattystyles 4y ago
    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?
    - AlotOfReading 4y ago
      The tuberculosis came from pacific seals, so no. I wouldn't put it past the llamas to have planned it though.
      - bigmattystyles 4y ago
        Good thing we have Winamp then.
  - nixcraft 4y ago
    >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.
    - LAC-Tech 4y ago
      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.
- photochemsyn 4y ago
  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-story-of-europeans-arrival 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. https://www.goodreads.com/book/show/39020.1491 https://www.goodreads.com/book/show/39020.1491
- billfruit 4y ago
  Syphilis is a disease thought to have come from the Americas to the Old World.
COGlory 4y ago
This ties in nicely with the Crohn's cold-chain hypothesis. https://pubmed.ncbi.nlm.nih.gov/32949122/ https://pubmed.ncbi.nlm.nih.gov/32949122/ It gives me hope that maybe one day we can figure some of these autoimmune issues out.
- carom 4y ago
  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.
  - ksidudwbw 4y ago
    If you factor in that we ran around with ringworms that emit immunosuppresants to protect themselves...
jacooper 4y ago
> 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.
- fooker 4y ago
  https://www.merriam-webster.com/dictionary/likely https://www.merriam-webster.com/dictionary/likely
- 344tgg4 4y ago
  Check out Dark Reader addon. https://darkreader.org/ 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.
  - jacooper 4y ago
    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.
paulpauper 4y ago
archive is a godsend. so many paywalls
- dang 4y ago
  We detached this comment from https://news.ycombinator.com/item?id=33294533 https://news.ycombinator.com/item?id=33294533.
Maursault 4y ago
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. [1] https://en.wikipedia.org/wiki/Plague_of_Justinian https://en.wikipedia.org/wiki/Plague_of_Justinian
- geneticdrift 4y ago
  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.
  - kzrdude 4y ago
    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.
  - Maursault 4y ago
    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.
- chrisco255 4y ago
  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.
samwestdev 4y ago
I wonder if the same thing will happen with COVID.
- notriddle 4y ago
  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.
  - quickthrower2 4y ago
    What about long covid?
  - RodgerTheGreat 4y ago
    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-be-among-the-top-10-causes-of-mortality-in-children-and-youth-in-the-United-States.aspx 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-2022-06-17-18/02-COVID-Fleming-Dutra-508.pdf https://www.cdc.gov/vaccines/acip/meetings/downloads/slides-... Looks like selective pressure to me.
- cm2187 4y ago
  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).
Baeocystin 4y ago
'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) https://en.wikipedia.org/wiki/Survival_of_the_Sickest_(book)
cm2187 4y ago
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.
- ndsipa_pomu 4y ago
  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.
- nine_k 4y ago
  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.
- mijamo 4y ago
  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.
- Archelaos 4y ago
  > ... 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.
Jenda_ 4y ago
Various similar examples of this: https://en.wikipedia.org/wiki/Heterozygote_advantage https://en.wikipedia.org/wiki/Heterozygote_advantage

76 points by Petiver 4y ago

Paywall free archive: https://archive.ph/xCfBT https://archive.ph/xCfBT

Expanding on this, CGP Grey had this amazing video (https://www.youtube.com/watch?v=JEYh5WACqEk 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.

AlotOfReading 4y ago
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.
- bigmattystyles 4y ago
  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?
  - AlotOfReading 4y ago
    The tuberculosis came from pacific seals, so no. I wouldn't put it past the llamas to have planned it though.
    - bigmattystyles 4y ago
      Good thing we have Winamp then.
- nixcraft 4y ago
  >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.
  - LAC-Tech 4y ago
    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.
photochemsyn 4y ago
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-story-of-europeans-arrival 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. https://www.goodreads.com/book/show/39020.1491 https://www.goodreads.com/book/show/39020.1491
billfruit 4y ago
Syphilis is a disease thought to have come from the Americas to the Old World.

COGlory 4y ago

This ties in nicely with the Crohn's cold-chain hypothesis. https://pubmed.ncbi.nlm.nih.gov/32949122/ https://pubmed.ncbi.nlm.nih.gov/32949122/ It gives me hope that maybe one day we can figure some of these autoimmune issues out.

carom 4y ago
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.
- ksidudwbw 4y ago
  If you factor in that we ran around with ringworms that emit immunosuppresants to protect themselves...

jacooper 4y ago

> 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.

fooker 4y ago
https://www.merriam-webster.com/dictionary/likely https://www.merriam-webster.com/dictionary/likely
344tgg4 4y ago
Check out Dark Reader addon. https://darkreader.org/ 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.
- jacooper 4y ago
  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.

paulpauper 4y ago

archive is a godsend. so many paywalls

dang 4y ago
We detached this comment from https://news.ycombinator.com/item?id=33294533 https://news.ycombinator.com/item?id=33294533.

Maursault 4y ago

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. [1] https://en.wikipedia.org/wiki/Plague_of_Justinian https://en.wikipedia.org/wiki/Plague_of_Justinian

geneticdrift 4y ago
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.
- kzrdude 4y ago
  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.
- Maursault 4y ago
  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.
chrisco255 4y ago
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.

samwestdev 4y ago

I wonder if the same thing will happen with COVID.

notriddle 4y ago
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.
- quickthrower2 4y ago
  What about long covid?
- RodgerTheGreat 4y ago
  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-be-among-the-top-10-causes-of-mortality-in-children-and-youth-in-the-United-States.aspx 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-2022-06-17-18/02-COVID-Fleming-Dutra-508.pdf https://www.cdc.gov/vaccines/acip/meetings/downloads/slides-... Looks like selective pressure to me.
cm2187 4y ago
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).

Baeocystin 4y ago

'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) https://en.wikipedia.org/wiki/Survival_of_the_Sickest_(book)

cm2187 4y ago

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.

ndsipa_pomu 4y ago
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.
nine_k 4y ago
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.
mijamo 4y ago
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.
Archelaos 4y ago
> ... 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.

Jenda_ 4y ago

Various similar examples of this: https://en.wikipedia.org/wiki/Heterozygote_advantage https://en.wikipedia.org/wiki/Heterozygote_advantage