The microorganisms that live in our gut are less diverse than they were 2,000 years ago.
This is one of the key findings from the genome analysis of fossilized human feces from rock shelters across North America and Mexico. Eight samples, aged between 1,000 and 2,000 years ago, revealed a microorganism that was totally new to science, like everyone else missing from today’s gut microbes.
In contrast, modern gut microbes had more antibiotic-resistant microorganisms than those of our ancestors. The findings could help us understand a link – if there is one – between our lower microbiome and a higher incidence of industrial chronic diseases such as diabetes and obesity.
The human microbiome is an intriguing and complex machine, and in recent years, scientists have discovered that it plays a more important role in keeping the body healthy than we previously knew. But our understanding of how the human microbiome changes over time is limited.
Enter fossilized feces, scientifically known as coprolites, although these fossils may look unpleasant. But it can also provide a wealth of information about the life of ancient animals, revealing complex information about food and intestinal parasites and diseases.
Additionally, there are some microorganisms in the gut, allowing anyone with the right tools to collect a full picture of the microbes. That̵7;s what an international team of microbiologists led by the Joslin Diabetes Center in the United States have done the greatest detail for ancient human gut microbiome.
The researchers led coprolites perfectly preserved at three rock shelters – the Boomerang Shelter in Utah, an unknown location somewhere in the American Southwest. (The samples were collected almost 100 years ago and are poorly labeled) and the La Cueva de los Muertos Chiquitos site in Durango, Mexico.
These coprolites were verified to be human using food analysis and dated using radiocarbon analysis. Scientists then worked on the extraction of valuable preserved DNA that could identify microbes.
The researchers succeeded in generating 498 microbial genomes, of which 181 were more likely to be born in the human gut than the surrounding soil.
Out of these sequences, 158 appeared to represent some of the different microbes. This was then compared to 789 microbiomes from the current community, both industrial and non-industrial communities.
The results are impressive. The ancient microbiome is not only But are only similar to microbes from modern non-industrial communities. But there are still strains not found in the modern microbiome.Of the 158 genomes, 61 are totally unknown to science, that’s almost 40 percent.
Researchers believe that diversity in this microbiome may have something to do with food diversity.
“In ancient cultures, the food you eat was very diverse and able to support a more diverse microbial accumulation,” says Alexsandar Kostic, a microbiologist at the Joslin Diabetes Center.
“But as you move into more industry and grocery eating, you lose a lot of the nutrients that help support a more diverse microbiome.”
Microbes also have some interesting differences. They have fewer genes involved in antibiotic resistance. But there are fewer genes to produce glycan-degrading proteins, a sugar molecule found in mucus.
The digestion of mucus in the colon has been linked to diseases such as Crohn’s disease, celiac disease, and ulcerative colitis.
Ancient microbes also had a higher number of transposes – enzymes that were able to cut and paste and replicate DNA elements, switching things around to help them adapt to changing conditions, among other things.
“We think this might be a strategy for microbes to adapt to a changing environment rather than the modern industrial microbiome, where we eat more or less the same thing and live the same life throughout the year,” Kostic said.
“As in more traditional environments, things change and microbes need to adapt, they may use larger vestibular groups to grab and assemble genes that will help them adapt to the condition. Different environments
The way the evolving microbiome may change our health is unclear and the sample size is relatively small. But studies have shown that we can use the copolyte to explore the guts of our ancestors to see what has changed. In turn, this could lead to better health outcomes in the future.
“Similar future studies that exploit the fertility of Palaeofakes not only But it will only expand our knowledge of the human microbiome. But it could also lead to the development of a way to restore current gut microbes to their ancestors, ”the team wrote in their paper.
The research is published in nature.