Is human body a super-organism?!

Krishna: Not entire human race. The human body? To some extent!

Recently somebody told me they feel lonely. This was my reply to them:

Do you think you are alone? NO! That is an illusion!

I definitely am not alone . Do you know there are billions, no trillions, of bacteria inside and on your body?

Thoroughly revised estimates show that the typical adult human body consists of about 30 trillion human cells and about 38 trillion bacteria(1). And that is just bacteria. There can be other microbes too. They all call your body their home!

Just because you cannot see them with your naked eyes, do you think you are alone?

The human body hosts vast microbial communities, termed the microbiome. Less well known is the fact that the human body also hosts vast numbers of different viruses, collectively termed the ‘virome’.

Image source: rauias.com

If you take a human body into account, these cells outnumber its own cells by a factor of ten and contain at least ten times more DNA than its own genome. In exchange for food and shelter, this symbiont provides the human body, the host, with metabolic functions far beyond the scope of its own physiological capabilities. In this respect the human body can be considered a superorganism; a communal group of human and microbial cells all working for the benefit of the collective - a view which most certainly attains liberation from self.

Mitochondria originated by permanent enslavement of purple non-sulphur bacteria (2). These endosymbionts became organelles through the origin of complex protein-import machinery and insertion into their inner membranes of protein carriers for extracting energy for the host.

Image source: Shutterstock

Human microbiota affects its entire system. They cause diseases but by understanding the entire process you could treat those same diseases by restoring a “healthy” microbiome. The microbiome can even influence how the body responds to medical treatment. For instance, a higher prevalence of specific strains of bacteria in the gut can improve the response rate for melanoma patients being treated with immunotherapy. These drugs are designed to boost the immune system response to fight cancer, and the presence of these bacteria appears to enhance the potency of immune T-cells as they infiltrate tumors and attack cancer cells (7).

The human genome contains billions of pieces of information and around 22,000 genes, but not all of it is, strictly speaking, human. Eight to ten percent of our DNA consists of remnants of ancient viruses, and another 40 percent is made up of repetitive strings of genetic letters that is also thought to have a viral origin (3).

Researchers found that stretches of viral DNA long embedded in the human genome can produce proteins that help block infection by viruses. Further identification and study of these protective virus-based proteins could provide new insights for fighting viral infections (4). Viral DNA in human genomes, embedded there from ancient infections, serve as antivirals that protect human cells against certain present-day viruses (5).

Viral DNA has played crucial roles in our evolution. Some of it was the source of the mammalian placenta. Other bits are involved in our immune response against disease and in the formation of new genes. Without viruses, humans could not have evolved to this extent(6).

A family of retroviruses called HERV-H are essential for pluripotency. However, they do not code for proteins. Instead, the HERV-H sequences are copied onto molecules called RNAs, and these keep the cell pluripotent. "If they are suppressed, then the cell morphology changes and it loses the ability to maintain its undifferentiated state" (6).

Other ERVs* regulate the activity of genes, and therefore control bodily processes. For example, our bodies use an enzyme called amylase to break down carbohydrates like starch in our food. We have amylase in the pancreas and we have amylase in the mouth in the saliva. The amylase gene is activated in the salivary gland by a DNA sequence called a promoter – which comes from an ERV (6).

A human body is highly evolved. Unlike virtually every other creature on Earth, we human beings do much more with energy than just power our own metabolism. We evolved even smarter brains, and the ensuing virtuous circle propelled our brains to the top of the class.

A human body is a superorganism in the sense that it obtained some of its unique characters by integrating with and incorporating other genetic material into its system. And also by hosting the microorganisms in its system. Most of all, with highly evolved brains, yes, we obtained lot of power.

So much power that we started “The Anthropocene Epoch” which is an unofficial unit of geologic time, used to describe the most recent period in Earth's history when human activity started to have a significant impact on the planet's climate and ecosystems.

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*Endogenous retroviruses (ERVs) are endogenous viral elements in the genome that closely resemble and can be derived from retroviruses.

Footnotes:

1. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4991899/#:~:text=Thoro...
2. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1634775/#:~:text=Mitoc...
3. The non-human living inside of you | Cold Spring Harbor Laboratory
4. Ancient viral DNA may help humans fight infections
5. http://John A. Frank, Manvendra Singh, Harrison B. Cullen, Raphael A. Kirou, Meriem Benkaddour-Boumzaouad, Jose L. Cortes, Jose Garcia Pérez, Carolyn B. Coyne, Cédric Feschotte. Evolution and antiviral activity of a human protein of retroviral origin. Science, 2022; 378 (6618): 422 DOI: 10.1126/science.abq7871
6. The viruses that helped to make you human
7. How the microbiome affects human health, explained