Role and Impact of the Microbiome on the Human Genome

Read about key concepts and views on the role and impact of our microbes’ genomes on our human genome!
3 recent papers to give you Food For Thought

Getting the Hologenome Concept Right: an Eco-Evolutionary Framework for Hosts and Their Microbiomes.

Theis R. K., et al. mSystems. Mar 2016. 

ABSTRACT
Given the complexity of host-microbiota symbioses, scientists and philosophers are asking questions at new biological levels of hierarchical organization—what is a holobiont and hologenome? When should this vocabulary be applied? Are these concepts a null hypothesis for host-microbe systems or limited to a certain spectrum of symbiotic interactions such as host-microbial coevolution? Critical discourse is necessary in this nascent area, but productive discourse requires that skeptics and proponents use the same lexicon. For instance, critiquing the hologenome concept is not synonymous with critiquing coevolution, and arguing that an entity is not a primary unit of selection dismisses the fact that the hologenome concept has always embraced multilevel selection. Holobionts and hologenomes are incontrovertible, multipartite entities that result from ecological, evolutionary, and genetic processes at various levels. They are not restricted to one special process but constitute a wider vocabulary and framework for host biology in light of the microbiome.

Impact of the Microbiome on the Human Genome.

Jeyakumar T, Beauchemin N, Gros P. Trends Parasitol. 2019 Oct.

HIGHLIGHTS
While the selective pressure exerted by pathogens on the human genome is clear, commensal microbes may have also helped humans adapt to changing environments, also leaving marks in the human genome.
Affordable genomic sequencing, and cataloging of microbial populations living on humans, is revealing an important human/microbiome interplay in health and disease.
The human microbiome plays a critical role in training and regulating the immune system to promote health and fitness. Certain human genetic variants that cause changes in microbial composition are also associated with diseases, suggesting that the microbiome may impact expression of disease-associated genetic variants in humans.
The microbiome may thus have influenced the retention or elimination of genetic variants affecting fitness, and may have contributed to sculpting the human genome.

The holobiont concept before Margulis.

Baedke J, Fábregas‐Tejeda A., Nieves Delgado A. COMMENTARY AND PERSPECTIVE in Journal of Experimental Zoology. 10 Feb 2020.

ABSTRACT
In recent years, Lynn Margulis has been credited in various articles as the person who introduced the concept of holobiont into biology in the early 1990s. Today, the origin of evolutionary studies on holobionts is closely linked to her name. However, Margulis was not the first person to use this concept in its current context. That honor goes to the German theoretical biologist Adolf Meyer‐Abich, who introduced the holobiont concept nearly 50 years before her (in 1943). Although nearly completely forgotten today, in the 1940–60s he developed a comprehensive theory of evolutionary change through “holobiosis.” It had a surprisingly modern outlook, as it not only addressed tenets of today’s evolutionary developmental biology (evo‐devo), like the origin of form and production of variation, but also anticipated key elements of Margulis’ later endosymbiotic theory. As the holobiont concept has become an important guiding concept for organizing research, labeling conferences, and publishing articles on host‐microbiota collectives and hologenomes, the field should become aware of the independent origin of this concept in the context of holistic biology of the 1940s.