Oetzi Has No Living Female Relatives
The 5,300-year-old mummy's maternal line appears to have originated and died out in the eastern Italian Alps.
Oetzi the Iceman has no living female relatives, as his maternal genetic branch is now extinct, says a new research into the genetic history of the 5,300-year-old mummy.
According to the study, the Iceman's maternal line appears to have originated and died out in the eastern Italian Alps. On the other hand, his paternal lineage is still observed in Europe, and new male relatives, alive and well, may be possibly added to the list of the mummy's descendants.
The announcement comes a week after researchers published the results of a genetic analysis which established the Copper Age man was infected with Helicobacter pylori, the pathogen that gives people gastritis and stomach ulcers.
Found in 1991 in a melting glacier in the Oetztal Alps (hence the name), the mummy is one of the most heavily investigated human corpses of all time.
Scientists discovered that Oetzi had brown eyes and very bad teeth, was lactose intolerant, had a genetic predisposition for an increased risk for coronary heart disease and probably had Lyme disease.
It's certain he died a violent death: In 2007, CT scans showed that an arrowhead had lacerated his left subclavian artery, leading to fast bleeding.
In 2012 a complete analysis of the mummy's Y chromosome, which is transmitted from fathers to their sons, revealed that Oetzi's paternal genetic line, named G2a, is still present in modern-day populations.
Questions remained about the Iceman's maternal lineage, which is named K1f.
"The mummy's mitochondrial DNA [which is passed from the mother's to her offspring] was the first to be analyzed in 1994," Valentina Coia, a biologist at the European Academy of Bolzano/Bozen (EURAC), said.
"It was relatively easy to analyze and - along with the Y chromosome - allows us to go back in time, telling us about the genetic history of an individual. Despite this, the genetic relationship between the Iceman's maternal lineage and lineages found in modern populations was not yet clear," she said.
To understand whether Oetzi's genetic maternal line has left its mark in current populations, Coia and EURAC colleagues, in collaboration with the Sapienza University of Rome and the University of Santiago de Compostela, compared the mummy's mitochondrial DNA with that from 1,077 individuals belonging to the K1 lineage.
Among the samples, 42 originated from the eastern Italian Alps -- in genetic continuity with the mummy.
The comparison revealed that neither the Iceman's lineage nor any other evolutionarily close lineages are present in modern populations, suggesting that Oetzi's maternal genetic branch is probably extinct.
"Interestingly, there is a contrast between the Iceman's maternal and paternal genetic heritage," the researchers wrote in Scientific Reports, an online open access journal of the Nature group.
They noted that while Oetzi's maternal lineage has disappeared, his paternal lineage is still observed in Europe, particularly in groups from the Mediterranean area, such as Sardinia and Corsica.
"How can this pattern be explained?" they wondered.
To investigate this point, Coia and colleagues compared Oetzi's mitochondrial DNA and Y chromosome with available data from numerous ancient samples found at 14 different archaeological sites throughout Europe.
It emerged that the Iceman's paternal lineage was very common in different regions in Europe during the Neolithic age, while his maternal line probably existed only in the eastern Alps.
Putting together the genetic data on the ancient and modern samples, the researchers were able to reconstruct a possible scenario to explain the Iceman's genetic history: Oetzi's paternal lineage, G2a, is part of an ancient genetic substrate that arrived in Europe from the Near East with the migrations of the first Neolithic peoples some 8,000 years ago.
Migrations after the Neolithic Age in Europe partially replaced G2a with other lineages, except in geographically isolated areas such as Sardinia.
The Iceman's maternal lineage, K1f, originated in the eastern Alps at least 5,300 years ago. The same migrations that partially replaced Oetzi's paternal lineage caused the extinction of K1f.
"The K1f branch may have been completely replaced by haplogroups that are frequent today," the researchers wrote.
The process was probably favored by a low population density during the Neolithic and the Copper Age in the Iceman's territory.
The groups from the eastern Alps significantly increased in size only some 2,000 years later, from the Bronze Age onwards, as shown by archaeological studies conducted in the territory inhabited by the Iceman.
New DNA analysis has revealed that Oetzi, the 5,300-year-old mummy discovered in a melting glacier in the Italian Alps 25 years ago, harbored a pathogen in his stomach when he was murdered. The bug,
, is common and gives people gastritis and stomach ulcers. In order to make the discovery, scientists completely defrosted the mummy and took samples of its stomach.
Eduard Egarter-Vigl and Albert Zink take a sample from the completely defrosted Iceman mummy in November 2010.
Researchers extract the DNA of the Iceman's stomach contents at the lab of the European Academy(EURAC) in north Italy's Bozen/Bolzano.
This detail of X-ray imaging reveals the Iceman's stomach and intestine.
This chart shows the concentrations of the
pathogen in the Iceman's stomach and intestine and the site of the muscle control sample. Further analysis showed that the train of
the Iceman harbored was a representative of the bacterial population of Asian origin that existed in Europe before hybridization. "This puts things into wonderful perspective for us with just one genome. We can say the waves of migrations that brought the African strain into Europe had not occurred, or had not occurred in earnest, by the time the Iceman was alive," Yoshan Moodley, at the University of Venda, South Africa, explained.