10 Microbiome Facts-What is a Microbiome?

10 Microbiome Facts

1. What is a Human Microbiome?
The human microbiome is the sum total of trillions of microbes, including bacteria, fungi, protozoa, viruses, and archaea, that naturally live on and inside the human body.

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2. Why is Microbiome important?
Take the case of carbohydrate-digesting enzymes. The human genome, has fewer than 20 enzymes for carbohydrate digestion. So, we cannot break down most of the carbohydrates. But the genome of a single gut bacterium, Bacteroides thetaiotaomicron has over 260 carbohydrate-digesting enzymes.
3. Our body is largely made up of microbes!
Scientists estimates that our body is composed of ~30 trillion human cells, but is host to around 100 trillion microbial cells that means less than third are human, 70-90% are microbial cells.
4. 99% of our unique genes are bacterial!
According to Human Genome project, our genome has ~22000 genes. Analysis of the human microbiome has revealed that there are 3.3 million unique genes in human gut alone which is 150 times more genes than in our genome.
5. What is Microbiome fingerprint?
Each individual has a unique microbiome composition, almost like a fingerprint with some core species present in all members of the species. This unique microbiome composition is reflective of many factors, including diet, genetics, medication use, and lifestyle. 
6. The microbiome evolves over time.
The microbiome begins to develop at birth and continues to evolve throughout one's lifetime influenced by many factors including diet, genetics, medication use, and lifestyle. A stable Gut microbiome is formed by around 2-3 years of age.
7. The most diverse microbiome is the gut microbiome
The gut microbiome is the largest and most diverse community of microbes, containing up to 1,000 different species. Majority of the species are found in the large intestine.
8. Microbiome is crucial for our survival
The microbiome plays a crucial role in human health, helping to digest food, produce vitamins, regulate the immune system, and protect against pathogens.
Imbalances or disruptions in the microbiome is linked to various health conditions, including obesity, diabetes, inflammatory bowel disease, and neurological disorders.
For example, the gut-brain connection is a complex, two-way network of nerves, chemicals, and microbes that links the brain and gut. It's often called the "second brain" because the enteric nervous system (ENS) in the gut plays an important role in both digestive and mental health. Gut microbes produces or induces the production of neurotransmitters that carries messages from gut to the brain. Microbiome imbalances can adversely affect this message transfer and normal functioning.
9. Advanced DNA sequencing technologies helped researchers to study the microbiome in detail, leading to new insights about its role in human health and disease.
10. Microbiome modulation through dietary changes, probiotics, or other interventions is an active area of research for improving human health and treating various conditions.

Reference

• Human Microbiome Project (HMP) https://commonfund.nih.gov/hmp
• Wong AC, Levy M. 2019. New Approaches to Microbiome-Based Therapies.
• Di Vincenzo, F., Del Gaudio, A., Petito, V. et al. Gut microbiota, intestinal permeability, and systemic inflammation: a narrative review. Intern Emerg Med 19, 275–293 (2024).
• https://www.amnh.org/explore/science-topics/microbiome-health
• Zhang ZJ, Cole CG, Coyne MJ, Lin H, Dylla N, Smith RC, Waligurski E, Ramaswamy R, Woodson C, Burgo V, Little JC, Moran D, Rose A, McMillin M, McSpadden E, Sundararajan A, Sidebottom AM, Pamer EG, Comstock LE. Comprehensive analyses of a large human gut Bacteroidales culture collection reveal species and strain level diversity and evolution. bioRxiv [Preprint]. 2024
• Ursell LK, Metcalf JL, Parfrey LW, Knight R. Defining the human microbiome. Nutr Rev. 2012 Aug;70