Genetic Conservation Across Species
The answer to questions about cross-species viral susceptibility lies in conserved biological mechanisms. Many biological mechanisms are conserved across species. The closer species are on the phylogenic tree, the more likely they are to have conserved biology. Humans are much more likely to be susceptible to viruses from bats than they are to viruses that infect insects. Some biological mechanisms are found across all species. While those genes or mechanisms might not tell us anything about viral susceptibility, we can use them to learn about other disease mechanisms.
A transcription factor called mediator complex subunit 12 (MED12) is one example of a gene found in humans and many different species of animals. MED12 regulates many genes since it interacts with RNA polymerase II4. In humans, germline mutations (mutations you are born with) in MED12 can lead to intellectual disability and physical abnormalities5. Somatic mutations (mutations you acquire) in MED12 can lead to prostate cancer and uterine tumors6. MED12 is required for normal cardiac function, a discovery made through experiments conducted on mice7.
We can learn something new about MED12 from many different organisms. From zebrafish, we learn that Med12 (also known as Trap230) plays an important role in facial development, contributing to formation of the neural crest, cartilage, and ears8. We can even study the role of Med12 in the regulation of oxytocin (the cuddle hormone) in zebrafish9.
As we go down the evolutionary chain, we find even more discoveries in the fruit fly, Drosophila melanogaster. Fruit fly studies find roles for MED12 in steroid regulation and heart and muscle signaling10. Mutations in MED12 cause problems with eye development11. A research group from Texas A&M University used D. melanogaster to study MED12. They found that the gene is downregulated by insulin signaling in obese women, increasing the risk of uterine tumors12.
Answers to the inner workings of human bodies can even be found by observing the lowly yeast. Studies of Saccharomyces cerevisiae reveal that MED12 is part of a larger complex called the Srb8-11 module13. Yeast have been used to study the role of MED12 in drug resistance14 and to understand its role in oxidative stress15.
Whether you are studying viruses, cancer, or facial development, data can be mined from experiments conducted with almost any species. Understanding how genes and mechanisms are conserved helps us better understand human biology and will equip us to better contribute to human health and wellbeing in the future.