Nature and Nurture

On Monday night, on NPR’s coronavirus question and answer show, a listener asked whether there might be something in African Americans’ unique vulnerability to sickle cell anemia that related to their high rates of infection—and death—with COVID-19. The medical person answering questions thought it an interesting observation that deserved study—she knew of none. The host then turned the conversation immediately to related environmental issues: jobs, neighborhoods, stress, diabetes, etc.

We—and especially those of us who think of ourselves as “liberals”—know that bad water, crowded living conditions, jobs that keep people cheek to jowl with others, overall poverty and its attendant diseases, and the well-documented conscious and unconscious racism in treatment by police, ambulance drivers, schools and the medical establishment—and the stress of it all—are significant factors in the high rates of infections among black and brown people. We lean to “nurture” for understanding.

Nevertheless, if there are genetic factors in addition to these social and environmental factors, we should know what they are. We might consider “nature.” It might help us learn more about the disease!

It’s a question I have been trying to ask in recent blog posts: Is there something genetic that makes some more susceptible to this coronavirus, something in the long string of genes that reaches to Africa (always) but then bobs and swerves across continents and climates, settles in South Asia where it learns to eschew milk; goes north and lightens the skin; hunkers in Europe and picks up some of Neanderthal; crosses to the “new world” in small numbers with—say some—a more limited number of DNA and RNA combinations; and then scrambles all up with slavery, conquest, and colonization? With all of this, is there something in the genes that is helping to make African Americans, Latinx, and American Indians more susceptible to this COVID-19?

Smallpox

In the 1990s, virologists determined genetic factors in indigenous Americans that might account for the super-high—unbelievable by many in the anthropological establishment—rates of death when old world infectious diseases came to the new world. Anthropologists had been divided between “High Counters”—those who thought the Americas might have had a pre-Columbian population of 70-90 million, and the “Low Counters” who thought the population numbers lower than 10 million. Low counters argued that the plague had only taken one-third of the European population; how could smallpox, measles, and other infectious diseases have taken 75 or 90 percent of indigenous Americans?

In 1491: New Revelations of the Americas Before Columbus, author Charles Mann says that the court of academic opinion is moving to the High Counters. He summarizes two forms of “vulnerabilities” to infectious diseases that spelled high mortality for Indigenous Americans. The first had to do with lack of exposure to specific diseases and their precursors, e.g. small pox, chicken pox, cow pox, etc. The second had to do with a more restricted range of genes, due to a relatively small number of original American immigrants from Asia. This meant there was “genetic homogeneity” among them, which had its positives: “In 1491 the Americans were apparently free or almost free of cystic fibrosis, Huntington’s chorea, newborn anemia, schizophrenia, asthma, and (possibly) juvenile diabetes, all of which have some genetic component.” (p. 114)

In a quick Google search, I learned that current studies of people in Mexico show a wide range of genetic variability, with percentage of pre-Columbian indigenous profiles being as high as 90 percent in some populations. I also learned that Puerto Ricans register 60 percent European, Dominicans have more African genes, etc. In my quick survey the studies found different susceptibilities to renal and lung diseases. So maybe the woman with the question about sickle cell had a point!

In a few conversations I have had with Indian friends now about COVID-19, I hear a concern that goes deeper than clean water, poverty and today’s virus. I hear a generational awareness, a feeling in the bones that goes back through family experiences with infectious diseases, back to the flu of 1918, back, in fact to the colonization period and original loss of life and land.

We—as a country and society—have never been very good at listening to Indians. And I think the same can be said of our listening skills with Africans and people we call Mexicans and Hispanics—people who trace ancestry to old California, Texas, Arizona, and New Mexico, to Central and South America. We—of European stock—are incredulous of the damage our infectious diseases inflicted on the New World—or we have left that all in the past. But maybe we should open ears to these people and cultures, and to the academics who plod away at old diseases and population numbers. Maybe we should look at nature while—not instead of—improving nurture.

 

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