After Hunt’s unusual flight home, Shanidar Z arrived safely at Cambridge University for digital scanning and will eventually be relocated to northern Iraq to be the centerpiece of a new museum. The skeleton could be up to 90,000 years old, but its DNA will be used to better understand modern human history, statistically analyzing and comparing ancient DNA with the genomes of modern populations, “to show when different population groups they separated “. says Hunt.
Once a population divides into two or more reproductively isolated groups, the genes in each new population will gradually evolve in new directions as a result of random genetic mutations and exposure to various environmental factors that prevent successful reproduction, entering contact with new diseases. , for example.
It is through work like this that scientists have been able to trace the migration of different populations of humans and groups of Neanderthals around the planet over the last 70,000 years, and have also been able to break some myths about their habits and patterns. migration. We now know that humans and Neanderthals crossed paths quite frequently, and that Neanderthal communities were probably more attentive and intelligent than we previously credited them with. According to Hunt, the evidence of burial rituals in Shanidar’s Cave “suggests the memory and that they cared for his wounded and sick limbs.”
Separately, analysis of ancient DNA against the modern human genome has revealed that we still carry some genetic sequences that were present in people who lived millennia ago. This analysis even helped identify a new subspecies of humans 12 years ago: this discovery of Denisovans, believed to have existed in Asia about 400,000 years ago, shows how much is still unknown about our human origins.
At the Francis Crick Institute in London, a major project is underway to create a reliable biobank of ancient human DNA to help build these discoveries. Population geneticist Pontus Skoglund is leading the £ 1.7 million ($ 2.1 million) project, which will sequence 1,000 old British genomes by collecting data from skeletal samples from the last 5,000 years, with the help of about 100 institutions in the UK. From the database, it hopes to determine how human genetics has changed over millennia in response to factors such as infectious diseases and changes in climate, diet, and migration.
“Part of that is looking for genetic traits that could have been beneficial to past humans during previous epidemics,” he says. “There is no doubt that we can learn something from this in our understanding of how we manage contemporary diseases and other outbreaks.”
The Skoglund team obtains its samples from archaeological excavations around the country or from museums with existing collections. Their favorite bones for sequencing are those found in our inner ear: “They are especially good at preserving DNA, as they are the least susceptible to microbial invasion and other factors that can cause DNA damage.” , explain.
The bones are shredded to pass through a sequencing machine in the same way as any DNA sample. But ancient DNA requires “specialized protocols: modern DNA has very long fragments that are basically intact, whereas with ancient DNA we only get on average about 35 percent of the total base pair.”