Ice Age survivors: Did our ancestors die out in Italy? It's possible

Two independent analyses of genetic data, both published in Nature on March 1, show incredibly comprehensive insights into the migrations of ancient Europeans. But there's one catch - they reach opposing conclusions.

One paper documents the migrations of Ice Age hunter-gatherers over 30,000 years. Researchers found that a particular ancestry (Grevattian) took shelter in Western Europe but died out on the Italian peninsula (southern Europe) following the Last Glacial Maximum, LGM, between 25,000 and 19,000 years ago. However, a second paper describes a 23,000-year-old male as evidence for genetic continuity of the Gravettian-associated ancestry in southern Europe on either side of the LGM. 

Where did modern humans flee during the last Ice Age?

In Europe, it is generally known that modern humans first appeared about 45,000 years ago. They survived difficult times as hunter-gatherers, like through the Last Glacial Maximum. Still, we don't know much about their movements and interactions due to a lack of human fossils.

Now, one paper by Cosimo Posth and colleagues analyzed the genomes of 356 ancient hunter-gatherers. This included new genomic data from 116 individuals from 14 countries in western and central Eurasia, dating from 35,000 to 5,000 years ago. 

Surprisingly, the research team found that populations from different regions associated with the Gravettian culture, which was widespread across the European continent between 32,000 and 24,000 years ago, were not closely related to each other. 

They found that populations from western and southwestern Europe (today's France and Iberia) differed from coexisting populations from central and southern Europe (today's Czech Republic and Italy).

They also found that the gene pool of the western Gravettian populations - associated with the Solutrean and Magdalenian cultures- stayed in southwestern Europe during the coldest period of the last Ice Age (between 25,000 and 19,000 years ago). 

The researchers claim they later spread north-eastward to the rest of Europe with the expansion of the Magdalenian culture after this period. Additionally, they discovered that hunter-gatherer populations associated with the Gravettian culture living in central and southern Europe are no longer genetically detectable after the LGM. 

Instead, "We find that individuals associated with a later culture, the Epigravettian, are genetically distinct from the area's previous inhabitants," said co-author He Yu in a press release.

The case of a 23,000-year-old male in southern Spain

Ancestry closely related to these Epigravettian-linked individuals started to spread over Europe about 14,000 years ago. According to the study, they substantially replaced the gene pool associated with the Magdalenian era.

Contrastingly, a second independent paper by Vanessa Villalba-Mouco and colleagues reports genome-wide data from 16 further individuals from southern Spain. This included a 23,000-year-old male individual from Cueva del Malalmuerzo associated with the Solutrean ancestry., suggesting genetic continuity on either side of the LGM.