Black Death Likely Altered European Genome -- Signatures from Two Distinct Populations

https://www.livescience.com/43063-black-death-roma-evolution.html

As we've learned in class, the persistence of certain alleles varies in humans based on the geographic / ecological context of their recent ancestry. In some populations, mutations may arise that are particularly protective or deleterious for their environment. Susceptibility to disease is one of, if not the biggest driver of human mortality. Occasionally, pandemics and epidemics can affect humanity on a global scale, ultimately resulting in a change in allele frequency due to selection for disease resistance or ability to recover.

The black plague was one such epidemic, wiping out ~30% of the world's population at the time. Certainly, there should exist genetic signatures of resistance to the epidemic -- some individuals were more or less prone to succumbing to the disease. But how to tease out those signatures?

An elegant study examined two distinct populations in the Netherlands, whose ancestors lived through the black plague in the exact same environment, but according to historical evidence, kept to themselves in terms of mate choice. One population was the Roma, who had migrated from northern India relatively shortly before the plague, and their Dutch natives. The researchers wanted to see if there were genes that were similar between the descendants of the native Dutch and Roma that also differed between the Roma descendants and the northern Indian population. The idea is that these genes may have conferred resistance to the plague and been selected for in both populations in the affected Netherlands, and that such genes would be much more concentrated in the Roma descendants than those of northern Indians from whom the Roma had split.

The researchers found one gene related to skin pigmentation, one gene that was pro-inflammatory, and a cluster of genes related to immune system function that met this criteria. The researchers believe that the immune system-related genes were selected for in both populations in the context of the plague, and that the pro-inflammatory gene may have been a boon to this effect, even if pro-inflammatory genes tend to be maladaptive under 'normal' circumstances.

Mack Hepker, Potluck 4/14/2019