NOV 27, 2019 1:24 PM PST

Humans Are Continuing to Evolve, Along With Immune-Related Diseases

WRITTEN BY: Carmen Leitch

Our immune system is essential for us to fight off pathogens, but the immune response can become dysregulated, and cause health problems. Some genetic mutations can help people fight off infections, but those same beneficial mutations may also make people more likely to have autoimmune disorders. Researchers have learned that the ancestry of Africans or Eurasians can influence the likelihood that people will develop diseases that involve the immune system. Our immune systems also appear to still be evolving in response to lifestyle and environment. The findings have been reported in Trends in Immunology.

Image credit: Pixabay

"In the past, people's lifespans were much shorter, so some of these inflammatory and autoimmune diseases that can appear in the second half of life were not so relevant," noted the first author of the study, Jorge Dominguez-Andres, a postdoctoral researcher at Radboud Institute for Molecular Life Science in the Netherlands. "Now that we live so much longer, we can see the consequences of infections that happened to our ancestors."

In this study, the researchers analyzed genetic alterations in people from different places where viral or bacterial diseases are common, and cause immune responses, which lead to inflammation. Sometimes those genetic changes make it harder for some pathogens to invade those communities. They can also be linked to the gradual emergence of inflammatory diseases like Lupus, Crohn's disease, or inflammatory bowel disease.  

"There seems to be a balance. Humans evolve to build defenses against diseases, but we are not able to stop disease from happening, so the benefit we obtain on one hand also makes us more sensitive to new diseases on the other hand," explained Dominguez-Andres. "Today, we are suffering or benefiting from defenses built into our DNA by our ancestors' immune systems fighting off infections or growing accustomed to new lifestyles."

The parasite that causes malaria, Plasmodium sp., has been infecting people in Africa for millions of years, for example. Evolution has had a hand in selecting people, over time, that are resistant to these infections, in whom more inflammation may be occurring. This has gradually led to a higher incidence of cardiovascular diseases like atherosclerosis in these populations.

Dominguez-Andres and the senior study author, Radboud University immunologist and evolutionary biologist Mihai Netea also noted that the ancestors of Eurasian populations bred with Neanderthals. People that still carry remnants of Neanderthal DNA can be less likely to get Staph infections or HIV-1. But those people are also more likely to have allergies and asthma. The changes in the immune system can have benefits and risks.

"We know a few things about what is happening at the genetic level in our ancestry, but we need more powerful technology. So, next-generation sequencing is bursting now and allowing us to study the interplay between DNA and host responses at much deeper levels," added Dominguez-Andres. "So, we are obtaining a much more comprehensive point of view."

Our immune systems are continuing to evolve. For example, hunter-gatherers may have higher levels of diversity in their gut microbiome compared to urbanized populations. Improvements in hygiene and sanitation have also reduced the number of infectious pathogens people might be exposed to, but there also seems to have been an increase in certain diseases like type 2 diabetes in areas that have undergone those shifts (which is discussed in the following video).

The scientists want to expand their research to look at other groups of people. "So far, all of the studies we went through are focused on populations with European and African descent, but they must also be extended to indigenous and other populations to improve the representation of human genetic diversity," said Dominguez-Andres. "Lifestyles and ecologic natures can really differ and influence immune responses. So, more work needs to be done."


Sources: AAAS/Eurekalert! via Cell Press, Trends in Immunology

About the Author
  • Experienced research scientist and technical expert with authorships on over 30 peer-reviewed publications, traveler to over 70 countries, published photographer and internationally-exhibited painter, volunteer trained in disaster-response, CPR and DV counseling.
You May Also Like
OCT 14, 2020
Genetics & Genomics
Robots Are Moving Developmental Biology Forward
OCT 14, 2020
Robots Are Moving Developmental Biology Forward
Researchers have created a robot that can analyze the effects of mutations that occur in portions of the genome that hel ...
OCT 25, 2020
Genetics & Genomics
A Purr-fect Domestic Cat Genome
OCT 25, 2020
A Purr-fect Domestic Cat Genome
There are thought to be more than 94 million cats in the US alone. Researchers have now improved the reference genome se ...
OCT 26, 2020
Genetics & Genomics
Does a 'Mismatch' Between Diet and Biology Cause Poor Health?
OCT 26, 2020
Does a 'Mismatch' Between Diet and Biology Cause Poor Health?
People that eat a 'paleo' diet operate under the idea that we should be eating more like our ancestors, and that metabol ...
NOV 02, 2020
Genetics & Genomics
Denisovan DNA Recovered From the Tibetan Plateau
NOV 02, 2020
Denisovan DNA Recovered From the Tibetan Plateau
Denisovans were ancient hominins that were discovered only recently, and they had a wider range than previously known.
NOV 10, 2020
Immunology
Genetic Profiling Reveals How Ebola Puts Immune Cells in a Chokehold
NOV 10, 2020
Genetic Profiling Reveals How Ebola Puts Immune Cells in a Chokehold
In the middle of 2020, yet another deadly Ebola outbreak was reported in the Democratic Republic of the Congo - the 11th ...
DEC 15, 2020
Plants & Animals
How an Insect Gained Its Wings
DEC 15, 2020
How an Insect Gained Its Wings
For decades, researchers have tried to understand how insect wings evolved. It seemed that none of the proposed explanat ...
Loading Comments...