The first study to show that a change in the microbiome can lead to a change in the body plan of an animal without Darwin


A recent study published in the journal Molecular Biology and Evolution has found that the body plan of a sponge can be reorganized in response to changes in its microbiome. The study, conducted by researchers at Ludwig-Maximilians-Universität München in Germany, used the autotrophic cyanosponge Lendenfeldia chondrodes as a model organism.

L. chondrodes is a common salt-water aquarium sponge that can exist in two different forms depending on the exposure of its tissues to light. In well-lit conditions, the sponge has a flattened, foliose morphology, while in shaded conditions, it has a thread-like morphology. The researchers found that this morphological change is correlated with a change in the sponge's microbiome.

In well-lit conditions, L. chondrodes hosts a large population of symbiotic cyanobacteria. These cyanobacteria provide the sponge with food and oxygen, and in return, the sponge provides the cyanobacteria with a safe place to live. However, when the sponge is shaded, the cyanobacteria population collapses. This collapse is accompanied by a change in the sponge's microbiome, with a decrease in the number of bacteria that are associated with the cyanobacteria and an increase in the number of bacteria that are not.

The researchers found that the morphological change from foliose to thread-like is associated with a number of changes in the sponge's physiology. For example, the thread-like sponges have a lower metabolic rate and a reduced number of choanocyte chambers (the chambers that filter water). The researchers believe that these changes are necessary for the sponge to survive in shaded conditions.

The study's findings suggest that the microbiome plays a significant role in the development and morphology of sponges. This is the first study to show that a change in the microbiome can lead to a change in the body plan of an animal. The findings have implications for our understanding of the evolution of sponges and other animals, as well as the role of the microbiome in animal development.

Here are some of the key takeaways from the study:

  • The body plan of a sponge can be reorganized in response to changes in its microbiome.

  • The microbiome of a sponge is affected by the availability of light.

  • The morphological change from foliose to thread-like is associated with a number of changes in the sponge's physiology.

  • The findings have implications for our understanding of the evolution of sponges and other animals, as well as the role of the microbiome in animal development.

https://academic.oup.com/mbe/article/40/6/msad138/7191912

Horizontal gene transfer (HGT) of transposable elements (TEs) can cause rapid adaptation outside of neo darwinism. Neo Darwinism is the theory of evolution that states that evolution occurs through the process of natural selection, which acts on genetic variation in populations. HGT, on the other hand, is the process of genes being transferred from one organism to another, not through reproduction.

TEs are mobile genetic elements that can insert themselves into the genomes of other organisms. They can cause rapid adaptation because they can be rapidly acquired and lost, and they can also be inserted into genes that are involved in important biological processes. For example, TEs have been shown to be involved in the evolution of antibiotic resistance in bacteria.

In the microbiome, HGT of TEs is thought to be an important mechanism for rapid adaptation to changing environmental conditions. For example, studies have shown that TEs can be transferred between bacteria and archaea in the gut microbiome, and that this can lead to the rapid evolution of new metabolic pathways.

HGT of TEs is therefore a powerful mechanism for rapid adaptation that can occur outside of neo darwinism. It is an important process to consider when studying the evolution of microbial communities.

The Microbiome and Evolution: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4789628/

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