areas affected by black death

Did the Black Plague Shape our Genetic Risk of Autoimmune Disease?

Jamie Fernandez

Ring a ring a rosey, a phrase echoing from a nursery rhyme, carries with it the weight of history, pointing back to one of the darkest periods in human history—the Black Plague. This catastrophic event, dominated by the Black Death in the 14th century, was unleashed by the bacterium Yersinia pestis. Spread through the bites of infected fleas carried by rats, it was the ships of the age, riddled with these rodents, that facilitated the global spread of this deadly disease.

Even in our modern times, the World Health Organization (WHO) estimates that the plague affects between one to two thousand people annually. However, it's no longer the scourge it once was, thanks to advancements in medicine and our evolving genetics. It brings to mind Charles Darwin's principle of natural selection, which suggests that environmental pressures favour the survival of those best suited to the current conditions, often those with advantageous genetic traits. This begs the question: did the survivors of the Black Plague carry genes that made them more resistant?

A groundbreaking study conducted in 2023 delved into this question. Researchers extracted and analyzed DNA from individuals buried in London and Denmark, who lived before, during, and after the plague's terror. Their findings centered on two variants of the ERAP2 gene. Type A of this gene was found to produce more gene product than type B, essentially enhancing the immune system's efficiency. Intriguingly, the study revealed that individuals carrying two copies of type A were more likely to survive the plague, suggesting a natural selection favoring this genetic variant.

Today, the prevalence of the Type A variant of the ERAP2 gene is a testament to its historical advantage. Yet, in an ironic twist of fate, our contemporary lifestyle, characterized by improved hygiene and reduced exposure to pathogens, has led to our immune systems becoming overly vigilant. This hyperactivity can result in the immune system mistakenly attacking the body, a phenomenon at the heart of autoimmune diseases. The ERAP2 gene, through its role in immune regulation, exhibits what is known as antagonistic pleiotropy—where a gene has both beneficial and adverse effects on our survival.

Understanding our genetic blueprint, particularly concerning autoimmune diseases, has never been more critical. The DNA Autoimmune Kit by BioCertica offers an opportunity to peer into your genetic predisposition towards autoimmune conditions. Armed with this knowledge, individuals can be vigilant for symptoms and seek early intervention, underlining the importance of genetics in our health narrative.

Our history, intertwined with episodes of disease and survival, has undeniably shaped our genetic makeup. While we cannot alter our genetic past, we can certainly influence our health's future by staying informed and proactive, highlighting the intricate dance between genetics, disease, and history.



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