If it seems like we’ve been genetically set up as the punchline for some sort of
grim cosmic joke, we may be right.
Apparently, if any of your ancestors survived the Black Plague (and if you have any European bloodlines, you can be pretty sure they did, or you wouldn’t be reading this), they apparently left you with a small IOU for that courtesy.
Recent research seems to indicate that the same genes that allowed those lucky few to escape the Black Death did so with a little snigger, because those same genes pushed certain other genetic variants forward, allowing them to become more common in survivors' descendants, as revealed by DNA from the Middle Ages.
And that DNA, having set up shop, as it were, in many of us, may make their modern carriers, the descendants of those lucky Black Plague survivors, more susceptible to various autoimmune diseases.
The Black Death, or bubonic plague, was a 14th century pandemic caused by the bacterium Yersinia pestis, which probably arrived in Europe from distant lands aboard trading ship’s disembarking rats (they like to browse interesting foreign cultures, too, and check out the local entertainment and cuisine), and killed an estimated 30% to 50% of the population of Europe in just under five years.
Altho another modern study seems to debunk the rat theory, arguing that it was human parasites that allowed the plague to spread so fast and so far ….. well, duhhhh, isn’t like it had its own little Bullet Trains …. but beyond blaming it on a possible beaver bite, the new theory largely begs the issue of where the first human parasitic presence, like lice and fleas, got their dose of the plague, so, you know …. grain of salt.
As an aside, it was from A Distant Mirror that I finally learned what a petard was, and why being hoisted by it was a life-changing experience …. totally changed my life.
OK, it didn’t, but it created an interesting aside ….
Back to what probably interests us all a lot more than the ancient history of a distant continent and island.
This genetic protection against the plague may have come at a cost. The version of the ERAP2 gene that protects against Y. pestis is also a known risk factor for Crohn’s disease and other autoimmune diseases like rheumatoid arthritis and lupus, among others as yet unenumerated.
And to make it even better, similar genetic trade-offs likely unfolded during other historic outbreaks, both before and after the horrors of the Black Death, like the Great Plague of London during the reign of Charles II, which was only finally eradicated by The Great Fire of London a bit over a year later, in 1666 …. there’s no record of Londoners expressing gratitude for that flaming intervention ….
'Black death' survivors had plague-resistant genes that may boost their descendants' risk of autoimmune disease
https://www.livescience.com/black-death-natural-selection-in-humans
