Millions of new genes identified in the human microbiome

The bacteria present on the various areas of human skin, a little example of interaction between the microbiome and human beings (Image Darryl Leja, NHGRI)
The bacteria present on the various areas of human skin, a little example of interaction between the microbiome and human beings (Image Darryl Leja, NHGRI)

An article published in the journal “Nature” describes a research on the human Microbiome, the whole group of microorganisms that live in the human body, sometimes in symbiosis with it but sometimes as parasites. A team of researchers from various American institutions analyzed a lot of microbes discovering millions of genes so far unknown. This will allow to take a leap forward in understanding their role in human’s health and in diseases.

The human body is full of microorganisms that sometimes have a significant influence on our health, yet we still know them in a limited way. Even the estimate of their amount is quite vague: there are those who claim that for every human cell there are 10 microbes but others estimate that there are 100 of them, in 2014 a group of researchers estimated they were “only” 3 while in 2016 another group of researchers estimated that the ratio between human cells and microbes was 1.3:1.

Progress in biological sciences and genetic analysis is allowing steps forward in this type of research but there are really a lot of species that live in the human body so the task is still very long and complex. In 2008, the American National Institutes Health launched the Human Microbiome Project (HMP) initiative, a five-year study to identify and study human microbes, better understand their relationship with their hosts’ health and obtain developments in the field of bioinformatics, the application of computer science to the biological field and therefore also of the medical one.

Among the participants in the HMP initiative there’s a group of researchers from the University of Maryland School of Medicine (UM SOM), Harvard T.H. Chan School of Public Health, the Broad Institute of MIT and Harvard, and the University of California San Diego. A first study was described in an article published in the journal “Nature” in 2012 but the work went well beyond the originally duration scheduled for the initiative.

In this new phase of the research, 1,635 new microbial samples were analyzed for a total of 2,355 samples taken over time from 265 people. The researchers sequenced the DNA of the organisms present in the samples to identify which are present in the various parts of the body to determine whether they change or are relatively stable over time and to understand their functions.

This study tripled the amount of human microbiome data compared to those previously analyzed, making it the largest study conducted so far in this field. The microorganisms in the human body are of a very diverse nature because they can be bacteria, viruses but also fungi, so their interactions with human organs are very different.

The potential advances from this study are remarkable but this is only the first stage of the work. Jason Lloyd-Price, the article’s lead author, pointed out that without information on variability or context the information about the microbiome collected so far haven’t immediately led to the creation of new drugs or therapies.

Anup Mahurkar, executive director of the Institute of Genome Sciences (IGS) at the University of Maryland School of Medicine, pointed out the complexity of the communities of organisms that live in the human body and stated that there’s always something more that we can learn. In short, this study is of the highest level but needs to follow-ups to bring benefits to our health.

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