AllysonDeMarcoReadingReport #1 The articles we read and discussed lastweek were “We Get By with a Little Help from Our (Little) Friends” by Ruby etal. and “Role of microorganisms in the evolution of animals and plants: thehologenome theory of evolution” by Zilber-Rosenberg and Rosenberg. The formerarticle’s main idea is that “we are not alone”, which essentially means thatour bodies and those of other complex organisms are home to a diverse ecosystemof microbes, which greatly influence our behavior (Ruby et. al, 1305). Severalexamples of interactions between microbes and hosts are offered, which allserve to emphasize the point that we would not be what we are today without ourmicrobes. The article also discusses the modern view of microbial symbioseswith regard to new research in the growing field. Today, scientists realizethat there are both pathogenic and mutualistic microbes which play importantroles in the evolution and behavior of complex organisms. Researchers arecontinuing to develop new approaches and better technology to understand thesereactions between microbes and their hosts.
Although researchers are hard atwork trying to improve research in this field, there are still many challengesahead. For example, some microbes can’t be cultured in a lab, which makesstudying those specific microbes much more difficult. Another challenge lieswithin the fact that several different disciplines are involved in microbialresearch, so it can be difficult to exchange information across so many fieldsof study. To improve research in the future, we need to work on integrating allof the different ideas and types of data coming from different disciplines inorder to advance the host-microbe interaction field as a whole. The second article that we read anddiscussed focuses on the hologenome theory of evolution which states that anindividual plant or animal is a community of the host and all of its symbiotic microbesand serves as a unit of selection in evolution (Zilber-Rosenberg &Rosenberg, 723). This community of microorganisms within the host is referredto as a holobiont, and it is a “unit of selection” because the geneticdiversity of microbial symbionts plays an important role in adaptation andevolution of higher organisms.
The hologenome can vary based on changes withinthe genome of the host or the microbes, which can be brought on by rapidchanges in the environment. During periods of environmental stress, the diversityof the microbial population may help the host survive, giving them sufficienttime to adapt and evolve to meet the demands of the changing environment. Thisis a potential benefit of a symbiotic relationship, but there could bedrawbacks as well. For example, in some cases the host and the microbe can’tsurvive without each other, so if an external factor damages either the host orthe microbe, the entire holobiont could suffer. Also, pathogenic microorganismscan cause infectious disease which directly harm the host. Due to the vastdiversity of both pathogenic and mutualistic microbes within a holobiont, wecan’t accurately describe the microbiome of an animal.
The microbiome isconstantly changing in response to environmental factors and genetic mutationand variation, which makes it impossible to tell exactly what microbes areinteracting with a host at any given time. Even though the microbial communityis always fluctuating, genomes are still passed on through generations.Therefore, any organism in close contact with offspring can transfer symbionts,influencing the next generation.
Although the microbes and host consistentlyinteract with each other, the microbial community can be regulated by the host.For example, bacteriophages and other opposing forces can limit and regulatewhich strains can survive and form meaningful interactions in the holobiont.The ultimate effect of being free of symbionts is that the organism withoutsymbionts would be left to evolve based on selection by random variants, whilethe holobiont has the ability to evolve by adaptation to changing environments. I enjoyed reading both of thearticles because I thought that although the concepts seemed difficult atfirst, the numerous examples given increased not only my understanding of themain ideas but also my overall interest in the topics.
For example, the secondarticle states how termites feed their feces to their offspring to transfersymbionts. The many examples given are both intriguing and demonstrate conceptsdescribed in the text. The first article also seemed very relevant in today’ssociety. For example, it gave the example of microbes within coral reefsprotecting them from damage, which is extremely important now as the coralreefs are beginning to die.
Finally, both articles discussed how the field willcontinue to adapt and improve in the future, which is something I’m veryinterested as a future researcher. Works CitedRuby, Edward, et al. “We Get By with a Little Help from Our(Little) Friends.” Science, 27 Feb.
2004, pp. 1305–1307. Zilber-Rosenberg, Illana, and Eugene Rosenberg.
“Role ofMicroorganisms in the Evolution of Animals and Plants: the Hologenome Theory ofEvolution.” Federation of European Microbiological Societies, pp.723–735.