We learn at school how to identify the different types of bacteria depending on what colour they turn when stained, where they live and / or whether they are circles or more oblong (cocci and rods) and what diseases they cause. Microbiologists isolate cultures in the lab in order to perform further tests to identify the strain and to see what antibiotics these bugs respond to (or not).
We have long known that the human body like any other healthy animal lives in harmony with the environment and the trillions of other organisms that live on, in and around us. We all help, home, nurture and protect each other because it is mutually advantageous (in the main) to do so. Most scientific studies into the human microbiome up until recently have been concerned about identifying the good bugs from the bad and the associated 'species' identity. Disease has historically been associated with a specific species of bug. This is after all the logical progression of things.
The research has focused on mapping the bacterial types to determine whether and how the presence of a given bacterial species might affect disease risk, but until recently the research did not go far enough as it only gave partial insight into the complexities of disease and health. Understanding how and whether genes at an individual microbial level affect natural balance and disease is now the way forward.
Our biodiversity defined über-organisms
Following big bacterial genome studies it is now becoming patently clear that just looking at the species hardly touches the surface. Each species has strains and each strain has sub-strains. In fact, in the same way that no two siblings have identical genes, nor do bugs. We all have our own microbial fingerprint. In a recent study that looked at mouth and oral samples from over 3,600 people, nearly 46M non-redundant genes were identified of which half were described as unique "singletons". These singletons came from sub-population-specific microbial strains. The scientists are referring to this number of unique genes as "staggering genetic heterogeneity". Not only are the singleton genes non-redundant, but they are even more enriched for functionality than the non-singletons, meaning that these genes and their host bugs are important. So, the microbiome is unique to every person. Not only is everybody unique, but so too are our bio-diversity defined uber-organisms.
The human gut is a hospitable environment that allows bacteria to thrive. Furthermore, the microbiome can communicate with us via the chemical mix it produces, the chemical mix can affect mood as well as cravings for certain types of food. It sort of gives you the right to feel kinda proprietorial over your own bacteria, and they too about you.
Estimating the number of genes that reside in the human microbiome might be difficult to identify. One calculation is around 232 million, while another suggested the number could be substantially higher.
There may be more genes in the collective human microbiome than stars in the observable universe, and at least half of these genes appear to be unique to each individual