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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?