About 50,000 years ago, a bunch of Neanderthals built a house – and a bathroom–than today is a rocky escarpment south of Valencia, Spain. In recent years, some of these paleo-poops, the oldest known to be of a human species, have been excavated and analyzed. Now, the researchers had a glimpse of the ecosystems that existed in the bowels of these first hominins, from a fecal deposit in the remains of a fire at the site.
More than 200 bacterial microorganisms were extracted from the old poop by an interdisciplinary team of archaeologists, microbiologists and anthropologists. The researchers found an impressive amount of consistency between the microbes resident in the Neanderthal gut and the type of microbes that populate the intestines of modern humans. This consistency shows that many tiny inhabitants of our interior are, in fact, long-time residents, who have lived in us for hundreds of thousands of years and have co-evolved with the hominids they inhabit. The research was Published in the journal Nature Communications Biology.
According to Marco Candela, a microbiologist at the University of Bologna and co-author of the article, the team wanted to “see which microbiomes are coevolving with the Homo lineage in evolutionary time. ”To do this, they looked for microbes that contemporary humans could share with Neanderthals.
Having an initial reconstruction of a human intestine is useful to contextualize the appearance of our microbiomes today; the researchers want to know which bacteria remained with us and which have completely disappeared from our internal ecosystems. Microorganisms with substantial staying power in the bowels of mammals have been called “old friends” in the mid 2000s, and its coevolution with us has been linked to the way humans have lived for hundreds of thousands of years.
G / O Media can receive a commission
The oldest data on the intestinal microbiome for humans are around 8,000 years old – not even preceding the last ice age, which ended about 11,000 years ago. This has put researchers in trouble when it comes to understanding the interior of our early ancestors. Neanderthal poop delays chronology by 40,000 years – just before Neanderthals as we know them disappear from the evolutionary record.
“The point is that we have identified some microorganisms that are shared between modern humans and Neanderthals,” said Candela. “This means that these microorganisms populate the intestine of the human lineage before the segregation of the Neanderthal and sapiens strains. “
An important finding in Neanderthal poop was the inclusion of bacteria producing short-chain fatty acids, many of which allow humans to extract extra energy from dietary fiber, and one of which the researchers suggest may have provided health benefits for mothers elderly women and their children. But just as good microbes hitchhike in our guts, so do the creators of hell – researchers have also found bacterial pathogens in the feces that still exist today, causing oral and dental diseases in modern humans.
According to Candela, the microbiomes of populations that live in a traditional and rural way, such as the Hazda, a group of hunter-gatherers in northern Tanzania, tend to have more similar entrails. On the other side are humans who live in urban environments, which isolate our insides and make our bacterial residents less similar from person to person. The article describes a total loss of bacterial diversity in the modern human intestine and a situation where each of our intestines is not communicating as they did in our evolutionary past. “Each of us is like an island,” said Candela.
Often, the human evolutionary path is heroically structured – among many primitive humans, ours was the only one to succeed. But, as the Neanderthal microbiome shows, we were hardly alone on this journey. Many microorganisms have followed suit.
“Based on these results, we can anticipate that the symbiotic depth of time between humans and some co-resident microbes is at least a million years,” wrote co-author Stephanie Schnorr in an article blog in research. “This implies a fixed physiological relationship that is linked to normal development and longevity health between humans and Neanderthals as an ancient legacy.”
Hopefully, more feces will be studied in the future, so that we can further unravel the guts that made us who we are. For now, we can be grateful that the findings are not crap.