Ruth E. Ley, et al., Nature Reviews Microbiology

A human gut is an extreme environment for the microorganisms. The authors try to find out whether the different habitat affects the microorganism or not by using published 16S rRNA data. They compare humans with other mammals, metazoan, and other free-living [...]]]> Worlds within worlds: evolution of the vertebrate gut microbiota

Ruth E. Ley, et al., Nature Reviews Microbiology

A human gut is an extreme environment for the microorganisms. The authors try to find out whether the different habitat affects the microorganism or not by using published 16S rRNA data. They compare humans with other mammals, metazoan, and other free-living microbial communities. Before the modern age, human’s diet is heavily related to the environment. They only consume the food from the seed or fruit. When the times files, the tools and technologies help people to have their favorable food without controlling by the environment. Therefore, the differences of microorganisms comminutes within humans, which live in distinct geographic location, are getting smaller. They compare the difference of facial microorganisms comminutes inter human and human with other mammals. The result supports the previous assumption.

They took 99,801 16S rRNA from 464 samples and 181 studies. The samples contain 202 samples in mammalian, 34 samples from large sequencing efforts if free-living communities, other human body habitats, the guts of non-mammal vertebrates and from the guts or whole body of diverse metazoan. They apply principal component analysis on the final sets.

The first principal component can separate vertebrate gut-associated communities from free-living communities. Almost entire nonvetebrate gut communities clustered with free-living communities. They conclude that mammals have a strong host phylogenetic effect on the structure of microbiota of arthropods. The third principal component can separate saline and non-saline free-living environmental communities.

The Firmicutes and Bacteroidetes are the most common and ubiquitous in vertebrate gut samples including human. The other types of sample also contain high abundance of Firmicutes and Bacteroidetes but other phyla tend to have highly represented in non-gut samples. The phylum-specific analysis indicate the gut samples of carnivores tend to cluster closer to free-living communities.

Finally, the authors say the globalization and frequented movement increase the microbial transmission. This phenomenon rapidly lost the biodiversity. Plants and animals are becoming extinct and microbial communities as well. It is very important to maintain those microorganisms, because recent research said that terrestrial microbial community composition change might be resulting in global change.

This is really an exhausted work to analysis such as large amount data. It is, however, important to do such large-scale study. I believe all the living species are connected together. We cannot live alone without other species. Save the earth, save yourself.

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