Researchers who analyzed the remains of 36 people who died from the plague in 16th-century Germany have uncovered the first evidence of an evolutionary adaptation process driven by the disease. A team from the University of Colorado and the Max Planck Institute collected DNA samples from the inner ear bones of many graves in the southern German city of Ellwangen that were destroyed by the plague.
They also collected DNA samples from 50 current city residents.
This allowed scientists to compare the frequency spectrum – the distribution of genes – in both dead and local people.
Among current residents, the researchers found evidence of the pathogen, likely a plague caused by Yersinia pestis, that caused changes in DNA.
Dr. Paul Norman, Senior Research Associate in the Division of Personalized Medicine at the University of Colorado School of Medicine, said: “We found that innate immunosuppressants increased the frequency in modern people from the city compared to the victims of the epidemic.
“This suggests that these marks may have evolved to fight the epidemic.
“We propose that these frequency changes may result from exposure to the plague in the 16th century.”
The discovery is the first to suggest that Y.pestis can induce evolutionary changes that produce immune-related genes over the course of a generation.
As the epidemic caused several outbreaks across Europe for 5,000 years, the researchers believe. “Immune genes may have been pre-screened in a population a long time ago. But it was recently selected based on an epidemic event, ”according to the University of Colorado.
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The research is published in the journal Molecular Biology and Evolution.
The results of the study said: “Although the epidemic death is very high without treatment, the epidemic is high. But it remains likely that certain individuals will be more protected from severe or vulnerable disease due to a wide range of natural immune determinants.
“In this case, the frequency change in alleles that occurred during one epidemic crisis may be evident as a genetic adaptation and can be detected in modern people.”
Then, this natural selection would likely induce changes in DNA frequency following the simulations.
Dr Norman said, “I think this study shows we can focus on these same family of genes in determining immunity in modern epidemics.
“We know these genes are heavily involved in driving infection resistance.
“It gives clarity on our own evolution, there will always be people against it.
“They did not get sick and died, and the human population had bounced back.”
However, the researchers don’t want people to feel guilty, especially in the current epidemic.
Dr. Norman continues: “I don’t want to exclude anyone from getting vaccinated for the current pandemic.
“It’s a safer bet than counting your genes to save your life.”