After Hunt’s unusual flight home, Shanidar Z safely reached the University of Cambridge for digital scanning and will eventually be transferred back to northern Iraq to be the centerpiece of a new museum. The skeleton may be up to 90,000 years old, but its DNA will be used to further understand modern human history – by analyzing and statistically comparing the ancient DNA with the genomes of modern populations, “to demonstrate when different population groups separated . ” Hunt says.
Once a population is divided into two or more reproductively isolated groups, the genes in each new population will gradually evolve in new directions due to random gene mutations as well as exposure to various environmental factors that prevent successful reproduction – coming into contact with new diseases, for example.
It is through work like this that scientists have been able to map the migration of different population groups of people and Neanderthal groups around the planet over the last 70,000 years, and also dispel some myths about their habits and migration patterns. We now know that humans and Neanderthals mingled quite commonly, and that Neanderthal communities were probably more caring and intelligent than we have previously given them the credit for. According to Huntevidence of burial rites at Shanidar Cave “suggests memory and that they cared for their wounded and sick members.”
Separately, analysis of ancient DNA against the modern human genome has revealed that we still carry some genetic sequences that were present in humans who lived millennia ago. Such an analysis even helped identify a new subspecies of humans 12 years ago – this discovery of Denisovansbelieved 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 on such discoveries. Population geneticist Pontus Skoglund is leading the £ 1.7 million ($ 2.1 million) project, which will sequence 1,000 ancient British genomes by collecting data from skeletal samples from the last 5,000 years with the help of around 100 other British institutions. From the database, he hopes to determine how human genetics have 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 may have been beneficial to former humans during previous epidemics,” he says. “There is no doubt that we can learn some of this in our understanding of how to deal with contemporary diseases and other outbreaks.”
Skoglund’s team collects their samples from archeological excavations around the country or from museums with existing collections. His preferred sequencing bones are those found in our inner ear: “These are particularly good at conserving DNA, as they are the least susceptible to microbial invasion and other factors that can cause DNA to deteriorate,” he explains. .
The bones are ground down to be run through a sequencing machine in much the same way as any DNA sample. But the old DNA requires “specialist protocols – modern DNA has very long fragments that are basically intact, whereas with old DNA we only get on average about 35 percent of the total base pairs.”