Scientists have been able to “read” for the first time the DNA of a person who died in the Roman city of Pompeii during the eruption of the Vesuvius volcano, in the year 79 AD It is a man in his 40s, with lesions probably caused by tuberculosis and a genome similar to that of the peoples that still inhabit the Mediterranean basin today, especially those of Central Italy and the island of Sardinia.
The analysis of the genetic material of the volcano victim has just been published in the specialized journal Scientific Reports by an international team of researchers. The work was coordinated by Gabriele Scorrano, from the University of Copenhagen (Denmark), and the Brazilian doctoral student Thomaz Pinotti, from the UFMG (Federal University of Minas Gerais), who is carrying out part of his research at the Danish institution, also participates.
Pinotti told the Sheet who is in Copenhagen to work on a project aimed at analyzing the DNA of ancient South American Indians, but has also started to collaborate with research on the inhabitants of Pompeii because of his familiarity with analysis of the Y chromosome (the mark of masculinity in the genome human) and the so-called mtDNA, or mitochondrial DNA. This second type of genetic material is present only in mitochondria, the “powerhouses” of cells, and is normally passed only from mother to daughter or son. Thus, the Y chromosome and mtDNA are useful for tracing, respectively, a person’s paternal and maternal lineages across generations.
The study team worked with the remains of people who were caught in the eruption of Vesuvius in one of the rooms of the so-called “Casa del Fabbro” (“House of the Blacksmith”, in Italian), a relatively modest residence compared to the mansions of wealthy Romans that also existed in the city. Two dead, a man in his 40s and a woman in her 50s, were found propped up in a corner of what appears to have been the house’s dining room. He measured 1.64 m, while the woman was 1.53 m, which is within the average of the inhabitants of the Roman Empire at that time.
The two must have died instantly when a cloud of volcanic ash, with a temperature of around 300 degrees Celsius, arrived in the city. This, of course, poses a challenge to attempts to obtain even “readable” genetic material. “As a professor here says, DNA is like ice cream: it lasts longer in the cold”, explains the Brazilian biologist. “So the context of the volcanic eruption is very bad for its preservation. It was surprising that the extraction and analysis went well, although we obviously do everything we can to make things work.”
To gain access to the victims’ DNA, they extracted material from the petrous bone, which is located at the base of the skull and is very dense, which helps protect the genetic material from outside influences. Even so, it was only possible to obtain the complete genome of the man who died in the “Casa del Fabbro”, although the DNA of the other person helped to confirm that she was indeed female, as indicated by the conformation of her skeleton.
Something similar happened in the case of skeletal injuries. The Pompeii resident’s fourth lumbar vertebra has damaged areas that are compatible with so-called tuberculous spondylitis, which happens when the tuberculosis-causing bacteria affect the bones and can even “bend” the victim’s spine.
“He probably had a lot of pain from it,” says Pinotti. The team was able to obtain ancient DNA fragments that appear to match the gender. Mycobacterium, which includes the tuberculosis microbe, but it was not possible to say with certainty that the DNA was really that of this bacterial species. “We already knew that it is something very difficult to detect in ancient individuals. Even in living people, you cannot find the DNA of the bacterium in 40% of the cases”, says the Brazilian.
Genomic analysis of the Pompeii man revealed that he carried a type of mtDNA that is now common in Sardinia, as well as a Y chromosome variant that is currently frequent in East Africa but also appears in the Middle East and, again, in Sardinia. , as well as on the island of Cyprus. On the other hand, genome-wide data show that he was genetically close to other inhabitants of Italy who lived during the Roman Empire and also to other Mediterranean populations such as Greeks and Turks.
“It’s very close to today’s Italians. The difference is that the current population of Italy seems more homogenized, while that of the Roman Empire has more variability, is less mixed, let’s say. And what seems is that precisely the connections between various regions brought for the Empire is what help in this mixture”, explains Pinotti.
