We understand that viral particles evolve and evade the immune defenses via genes they inherit from their parents that have interacted with the human host. On the other hand, immune cells are thought to become more efficient at identifying and destroying microbes via the transfer of genes from the parents to their descendants. This model of transfer of the genome is called vertical transmission by scientists. Well, new evidence suggests that there is now what is known as horizontal gene transfer (HGT), which is the passage of genomes from viruses to the host cells and vice versa. Of course, this approach cuts both ways: it helps the virus sharpen its infectivity while helping the immune cells become more effective.
Viruses
The exchange that sparked the evolution
In the past, researchers only demonstrated HGT between bacteria and viruses and described the role it plays in the transfer of genomes in bacteria. But new research demonstrates the interchange of genes between viruses and eukaryotes like plants, fungi, and animals.
The erudite Dr. Irwin Nicholas, the lead author of the study, explained that scientists have always known the viral gene played a pivotal part in the evolution of viruses and eukaryotes alike. Also, viral genes possessed by humans play key roles in growth and mental well-being.
The researchers’ mission was to comprehend how this interaction between viruses and eukaryotes progressed. As such, researchers had to cross-examine viral to eukaryotic DNA transfer in several eukaryotic cells. The search revealed several genes that were transferred from viruses to eukaryotes and vice versa. Also, the scientists noticed that for every one transfer from virus to eukaryotes, there were two gene transmissions in the opposite way.
Dr. Patrick Keeling, one of the study’s lead authors, said, “By studying the function of these genes, we were able to make predictions about how these viruses affect their hosts during infection.”
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Unlike viruses, eukaryotes do not retain much of this viral DNA; notwithstanding, the importance of this transmitted DNA in human evolution cannot be doubted.
At the core, the viral genes continuously modify different structures in different organisms. Like it or not, viruses have played a major role in driving evolution so far. These jumps of genes are key in helping an organism acquire new abilities much faster than mutation could afford
Surprisingly, coronavirus and Zika virus do not transmit genes via HGT; however, they still manipulate similar genomes in their host tissues via many sophisticated mechanisms.
Clinical significance
Apart from the evolutionary implication of horizontal gene transmission, it has important health benefits. Research into these genes can provide valuable information on the evolution of pathogens and infection processes, and how to produce more effective therapy and stop drug resistance.
Conclusion
The research explains, to a great extent, the leaps in evolution taken by some microbes. Hopefully, it can help us keep those microbes in check.
Reference
Irwin, N.A.T., Pittis, A.A., Richards, T.A. et al. Systematic evaluation of horizontal gene transfer between eukaryotes and viruses. Nat Microbiol 7, 327–336 (2022). https://doi.org/10.1038/s41564-021-01026-3
