Exploring evolutionary immunogenomics: Lessons from our ancestors and past pandemics
Dr. Luis Barreiro
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Analysis by Miles Norsworthy:
It is uncontroversial to say that one of the greatest evolutionary pressures found in human civilization is resistance to disease. The increase of human population density due to advances in agrarian technology was coupled with an increase of communicable diseases. The lab of Dr. Luis Barreiro sought to identify those alleles that changed in response to various diseases at different points in time.
Dr. Barreiro first demonstrated the importance of controlling diseases in the population by comparing life expectancies between neolithic era humans and humans just prior to the development of various pathogen countermeasures such as antibiotics and pasteurization. Both those using stone tools and the steam engine suffered short and brutal life spans while those living shortly after the 1860s benefited from the previously mentioned new technologies that nearly abolished child mortality and greatly extended typical lifespans. Coupling the significance of diseases on a human population and the variety of diseases different populations may encounter based on geography, Dr. Barreiro’s lab decided to quantify the responses of different groups in response to influenza and listeria.
The two populations in question were those of African and European descent with many people sharing a good deal of both ancestries. The lab derived macrophages from 175 such individuals, exposed them to influenza and listeria, and quantified the differences in expression of a multitude of genes. As expected, the two populations reacted differently to pathogen stimulus with ~20% of alleles associated with African ancestry having much higher expression compared to alleles associated with European ancestry.
The Barreiro lab was also able to find similar results with other diseases such as the black death and, more recently, COVID-19. Even when controlling for various factors such as age, location, etc., there were significant differences in immune-related allele behavior between groups with different ancestries. As medicine becomes more personalized, this work and others like it will be essential to best understand the progression of a disease and the best way to treat it.