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rjmsci OP t1_isyb6bu wrote

Sixth-grader explanation: We all have different types of genes, called alleles. Some alleles can be useful in certain situations. In medieval Eurasia, it seems that having some alleles helped people not die of the Black Death. That means that after the Black Death, those alleles became more common. However, nowadays, those more common alleles are now unhelpful as they may increase the risk of getting autoimmune conditions. Hope that helps!


phormix t1_iszgw47 wrote

I recall seeing an article for these in regards to HIV and a historic condition (might have also been the black death), where it was believed that people with a particular mutation that made them resistant/immune was do to a mutation associated with plague survivors


Total-News3680 t1_it09q3q wrote

Thats a very specific mutation,a change in the CD4 protein , preventing HIV from locking onto the T4 cell. Its i. Less than 2 % of the population. Had it arisen with black plague it would be much more common.


theboredbiochemist t1_it20wim wrote

Just to add some more details, CCR5-delta32 had been suggested by some to have links to the Black Plague, but as stated in the linked publication, historical evidence and geographic distribution of the allele suggest otherwise, as you alluded to. Still an interesting mutation though and I look forward to seeing what researchers uncover as to why this allele has higher frequencies among some population subgroups and if it is linked to other variants in those populations.


SemanticTriangle t1_isykwgd wrote

Are they unhelpful, though? Are these alleles so specific to bubonic plague that they don't help with other communicable diseases?


666pool t1_isz3v2p wrote

Think of it as over active immune systems. Those who had over active immune systems had a better chance in fighting off bubonic plague, but also greater chance to fight their own body.


haleysname t1_isza5k6 wrote

anecdotal: type 1 diabetic for 34 years, I never get sick. Haven't even gotten Covid and worked the entire last few years in essential retail face to face with the unwashed masses.


CHUNKY_DINGUS t1_iszs2h9 wrote

Same!! Also a T1D, I NEVER get sick, I've never gotten covid despite multiple exposures, and from my family genealogy I know that I am the descendent of plague survivors.

Edit: It's funny, my dad was telling me that our ancestors were plague survivors just this morning before I read this!


haleysname t1_iszuw9g wrote

That's really cool! I haven't done any genealogy research for my family.

I'm gonna say we have super powers with side effects. Still worth it.


But also, I feel like I've always been told if I do get the flu (or whatever) I'm way more likely to die from it, so obviously, I'm still vaccinated as much as possible.


Total-News3680 t1_it0arwu wrote

So it's coincidental , TD1 and your immune strength.


shoestars t1_it1zrgq wrote

Well type 1 diabetes is an immune related condition


Total-News3680 t1_it5rqd8 wrote

Yes. I was thinking it was a question of regulation of the immune response rather than its intrinsic strength, but regulation js part of its intrinsic strength.


tiktalyk t1_it1eut2 wrote

My family has a history with autoimmune diseases. At least one Type 1 Diabetic in every generation, sometimes multiple, I have a brother with Crohn’s, lots of allergies popping up in the family such as Aloe Vera and Almonds, plus family history has a crazy overreaction to the 1918 Flu.

I don’t pick up diseases that easily. I’ve gotten exposed to Covid multiple times, I usually have relatively mild cold and flu symptoms if I get it at all.

Of course I also got migraines with aura, so it’s not as if I don’t get sick, it’s just that my usual sick is more of a brain malfunction instead of a pathogen.


Abject-Armadillo-496 t1_it03uzk wrote

And apparently having covid can increase your chances of developing type 2 diabetes? I read that somewhere ..


Total-News3680 t1_it0awhm wrote

Its a little soon to draw that conclusion i think.


Doctrevil t1_it13bzg wrote

Well I mean technically if you had COVID you have a higher likelihood of never getting a chance to get type 2 diabetes


Total-News3680 t1_it1p7wu wrote

Especially if you are of the mindset that believes getting Covid is the best way to develop immunity to covid.


SqeeSqee t1_isymjcz wrote

They said 6th grade explanation. it's obviously more complex than that, but they got the basics across.


UrbanArcologist t1_isywrtu wrote

They may help fight diseases of all kinds critical to mature enough to reproduce. After that natural selection isn't a factor. Can't imagine life expectancy was very high in the dark ages.


666pool t1_isz40gr wrote

It actually was once you got through childhood.


Du_ds t1_iszcoco wrote

If you lived to adulthood, you could expect a much longer life than average because the average is so skewed by all the dying in childhood.


666pool t1_iszqtme wrote

That’s not what I’m saying at all. Even the Romans had an average life expectancy of like 70+ if they made it to adulthood, which is not terribly dissimilar from today.


tampering t1_it0eiop wrote

Probably not specific, but plague was so deadly that it killed a lot of people without the mutation, so it became more widespread in the population where there were high rates of bubonic plague.

Let's say hypothetically the mutation is also helpful against a common upper respiratory infection. but having it means you only have the sniffles twice a year versus three times a year. Lacking that sort of helpfulness doesn't prevent an individual from passing on their genes to the next gen.


pez5150 t1_iszvxjq wrote

Makes you think about how helping people survive through plagues can make our gene pool healthier in the long run.


The_Goondocks t1_it03uk6 wrote

So if my ancestors died from the Black Plague, I wouldn't have Crohn's now?


Total-News3680 t1_it0bj93 wrote

Not necessarily. There could be other factors in the cause of Crohns, which is a modern disease


dumdum1066 t1_it0esbo wrote

Wouldn't necessarily agree that Crohn's is a modern disease but the 20th century provided the necessary advance in knowledge and technology to characterize the disease and understand the underlying cause. Yes, other factors may contribute to Crohn's.

-not an expert but my mother died from Crohn's and I have UC.


Hike_it_Out52 t1_isybi08 wrote

It definitely did... for other people I'm sure. Anyway, have an oddly appropriate award!


Swizzystick t1_it14anu wrote

So the black death may have spared our ancestors but it went after their offspring. What a world.


NEIC_ADMIN t1_it2ulj3 wrote

How does having Crohn's help you survive the plague?


rjmsci OP t1_isy2i0z wrote


4BigData t1_iszl867 wrote

Some people are not even testing positive for COVID while taking care of infected family members, wondering what genetic advantage they have.

I know that those with O negative blood types are the ones who deal better with COVID symptoms,CI%2C%200.78%E2%80%930.97).


Hendriks0709 t1_iszsqjq wrote

I can only speak for myself but 100% agree with both. My dad's side the family is from Europe originally but came to US 2 generations ago(so probably have an ancestor that survived the black plague). I am also have O- blood. At one point LAST Christmas we had a family gathering and all 9 family members in the house we stayed at got covid aside from me, I just took care of them. Of all the ones there I was the only O-


4BigData t1_iszsz43 wrote

And you never tested positive?

If so, that's also my story. I couldn't believe I got one negative test result after another


Hendriks0709 t1_isztl3i wrote

Not from that Christmas. I did test positive once as part of a medical trial but the Dr had me retest 24 hours later and it was negative then again another 24 hours after that also negative so he said the first one was a false positive.


4BigData t1_isztw0q wrote

Makes sense. I haven't gotten even a false positive yet. We'll see how that changes as new varieties keep on trying to get me.


Hendriks0709 t1_iszua5j wrote

So far I've also got all the vaccines and boosters with no side effects or symptoms. GF says I should get checked to see if I was born with natural immunity to covid. Guess we shall see how long we both keep our streaks running.


4BigData t1_iszw1ee wrote

I only got 3 vaccines total and stopped because the idea of a few countries having many vaccines per capita while third world countries having few and air travel resuming didn't make sense to me at all.

Vaccines should be more evenly distributed IMHO

By mid-2022, just over three per cent of people in low-income countries had been vaccinated with at least one dose, compared to 60.18 per cent in high-income countries.


xiledone t1_it01xmi wrote

No one's born with natural immunity to it that we know of.

I have type O+ and got super sick. (Was double vaccinated)

The blood type and covid study has been debunked countless times.


vanyali t1_it10ggl wrote

I am type O too but I’ve had COVID twice, the last time after fully vaxxed and double boosted. My whole family has type O blood and we were all symptomatic both times. Type O blood isn’t magic.


Hendriks0709 t1_it1pfxr wrote

Blood type is a bit more complicated then that, there are a total of 36 different blood group systems each containing or not containing certain antigens. So even amongst type O blood there are still rarer types of type O blood. People with type O- blood are just more likely to not have certain antigens which viruses bind to in a person's blood. So first question of you being type O would be are you O+ or O-? Then if you're O- which of the possible 61 antigens found on the Rh blood group system do you not have. You can request this info if/when you are getting blood work done.

I for instance would be O Rhnull, I don't have any of the 61 antigens found on the Rh blood group which makes my blood even more rare even amongst the O- group already. Bad side is I can't accept O- blood from others who do have Rh antigens because my immune system would reject it. Bright side my system is more resistant to viruses in general. Not immune I just generally get hit less hard then others and am less likely to get viral infections under the same circumstances as others.


4BigData t1_it2e7rr wrote

So interesting! Thanks for explaining it so clearly


outkast2 t1_it029i6 wrote

I'm glad to see this getting more acknowledgement because I mentioned the O type blood several times in the past and got heavily downvvoted.


4BigData t1_it0dqzy wrote

>got heavily downvoted.

why? blood type envy? Being 0 negative has its drawbacks too, everybody wants your blood and it seems to be a permanent emergency-level scarcity of it

It's not that much fun to be remembered by society only when our blood is necessary, which seems to be always


Hike_it_Out52 t1_isy95fo wrote

Hmm, very interesting. Please, obviously for other people who may see this post, explain it like you would to a Sixth grader. Use pictures as needed.


CletusDSpuckler t1_isyba6h wrote

Genes that may have helped you survive the bubonic plague centuries ago became more common in the genome because of that protective benefit. Today, those same genes may be partly responsible for a hyperactive immune system that causes auto-immune diseases like Chron's.


confuseray t1_isygnpw wrote

Genes that help survive black death were good back then. Times change. Same genes that help survive black death today now give you Crohns.


Welmarian t1_iszhyda wrote

Not sure people lived long enough back then to be familiar with autoimmune diseases that generally affect people near 50. Only a 50% chance of living to 50-55. Not the best odds. (Though autoimmune can span any duration of life, no doubt)


Village_Bear t1_it01coa wrote

Crohn's (and other autoimmune disease s) typically are onset between 20-30 years old. That being said, there are other factors in today's society that wouldn't have existed in the middle ages that are suspect triggers for autoimmune diseases. It also goes without saying that medical comprehension/diagnostics was not remotely what it is today.


Ry715 t1_isyee45 wrote

I wonder if more diseases do this as well? It seems like we are having a jump in autoimmune disorders post covid.


FetusDrive t1_isygo3m wrote

you wouldn't notice this right away. It would mean the people who had protections against autoimmune disorders would have made it moreso that they die from COVID meaning they wouldn't pass on those genes. So the people who are protected from COVID who don't die will pass on those genes.

So you wouldn't notice this uptick until generations down the line.


Foxs-In-A-Trenchcoat t1_isyn2cj wrote

Covid killed mostly older people who already had children, so it wouldn't be a selection pressure.


DuncanYoudaho t1_isz0i28 wrote

Yes and no. Older people that don’t breed help raise younger people and increase their fitness. Or so the theory goes.


Foxs-In-A-Trenchcoat t1_isz0tzv wrote

Probably doesn't matter much in first world countries.


GlobeTrekking t1_iszfcsg wrote

Agreed. Especially with an average age of death in developed countries of around 78 years old.


Welmarian t1_iszhpj0 wrote

I'd bet money the average age of death is drastically reduced after recurring Covid infections. If you consider it's a vascular disease, and the side effects that are reminiscent of trauma, repeated trauma leads to prematurely mortality. Thus, repeated Covid infections would in theory do the same.


NEIC_ADMIN t1_it2uzxc wrote

In Northern European and England-offshoot nations, grandparents mostly don't help with raising kids.

If most people dying are 60+ it's not natural selection. Parents of minors are mostly in their 30s, 40s, and 50s.


DuncanYoudaho t1_it30r4k wrote

“Raising kids” can be as small as babysitting for date night. Or allowing someone to borrow a car for a doctor appointment.


Freakinlasers t1_isyjqkv wrote

To tack on to what the other poster said, while we wouldn’t see this type of selection for generations, we may see more active autoimmune conditions simply because viruses can trigger autoimmunity.


Sparkletorch t1_iszivkx wrote

I’ve 2 autoimmune diseases. Ancestors must of got lucky with the plague then!


Fair_Banana2244 t1_it138z2 wrote

My ancestors survived the plague and all I got was this stupid autoimmune disease


Doridar t1_iszb0fq wrote

I recall a research from the hight of AIDS pandemic about descendants of bubonic plague survivors who had différent T cells that gave them protection against HIV infection. If I remember it correctely, it was a recessive transmission. Should you have both genes, You were fully protected; only from one parent, you could be infected but would but develop the disease


Kytyngurl2 t1_it0785j wrote

Reminds me of the connection between sickle cell and not getting malaria


dumdum1066 t1_it0j0is wrote

As irony would have it, we must now take drugs to suppress our magic immune systems that so wonderfully saved our ancestors. I'd like to imagine that some disease ravaged survivor of the future will thank me and my peers for braving the years of steroids and biologics and so not perishing from my autoimmune disease and preserving our super active immune systems.


_BlueFire_ t1_it1rb5f wrote

Interesting analogue fact: that's happening even on the present day: in African countries there are higher rates of anemia, since you get a higher possibility to survive/not develop malaria


jen4k2 t1_it2zu4r wrote

This is why a study of the Humanities, particularly history, along with hard sciences is so important: it provides an incredible context for understanding how science affects people.

Interdisciplinary Studies FTW!

Edit: Compulsory book recommendation to ground our understanding in storytelling! Doomsday Book, Connie Willis


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elucify t1_it1evm5 wrote

Black Death is the gift that keeps on giving.


Fleironymus t1_it1ikp8 wrote

I'm curious about whether or not this finding would fit with the hygene hypothesis, or whether they could be linked somehow.

For example, if the ones that survived were statistically cleaner, could that genetic bottleneck have somehow reinforced the effects of living without parasites? Or perhaps could these concepts be related some other way?


invisiblesock t1_iszg63i wrote

so now we need a disease that selects against these variants. problem solved! I love science.


Xyvexa t1_it0kgx1 wrote

So Pete Davidson can blame a ancestor for the problems with his butt tube?


TheRealBlerb t1_it0oe05 wrote

The planet has always been trying to help us, but we’ve become so complex in comparison to our ancestors that we can’t help ourselves.