Some human diseases are of ancient origin – malaria, TB, leprosy. Others seem to have popped up more recently - ebola moved into humans this century.
Some diseases were tricky to pin down for place of origin, once a number of long routes of trade and exploration opened. Syphilis spread in Europe notably after 1494, just after the voyages of Columbus. Did it originate in the Americas, or was it being spread there by the invading Europeans? Syphilis is part of a complex of disfiguring and debilitating diseases all caused by varieties of one bacterial species, Treponema pallidum.
The bacteria also causes yaws, bejel, and pinta. Rodrigo Baquera and 31 colleagues in 9 nations on 4 continents took a detailed look at DNA sample sin bones dated back to about 1200 CE. The bones came from 41 locations in Mexico, 39 in Chile, and 1 in Argentina. The researchers developed what’s called a molecular phylogeny – a graphthat places each variant on a branching “tree.” Modern computational tools figure out who’s related to whom and when the variants diverged, based on the simplest set of changes in individual DNA bases that links them all.
That evidence points to these regrettable diseases as having been established in the Americas prior to the arrival of the conquistadors.
This has been an outreach activity of the Las Cruces Academy, viewable at GreatSchools.org.
Source: Nature, 3 April 2025, pp. 186 ff.
