After Hunt’s unusual flight home, Shanidar Z arrived safely at Cambridge University for a digital scan, which will eventually be transferred back to northern Iraq to become the heart of the new museum. The skeleton may be 90,000 years old, but its DNA will be used to learn more about modern human history—by analyzing and statistically comparing ancient DNA with the genomes of modern populations “to demonstrate when different populations parted ways,” Hunter said.
Once a population splits into two or more reproductively isolated groups, the genes in each new population will gradually evolve in new directions due to random genetic mutation and exposure to various environmental factors that hinder successful reproduction – exposure to new disease, eg.
It is through work like this that scientists have been able to map the migrations of different human and Neanderthal groups on Earth over the past 70,000 years and debunk some of the myths about their habits and migration patterns. We now know that humans and Neanderthals interbred very commonly, and that the Neanderthal community was probably more caring and intelligent than we previously thought. According to Hunter, evidence of the Shanidar Cave burial ritual “suggests that they had memories and they cared for wounded and sick members.”
In addition, analysis of ancient DNA against modern human genomes shows that we still carry some genetic sequences that existed in humans thousands of years ago. The analysis even helped identify a new human subspecies 12 years ago, the discovery of Denisovans, believed to have existed in Asia around 400,000 years ago, suggesting that our human origins still remain. How many unknowns are there.
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 these findings. Population geneticist Pontus Skoglund is leading the £1.7m ($2.1m) project, which will examine 1,000 ancient British The genome is sequenced. From the database, he hopes to determine how human genes have changed over millennia in response to infectious diseases and factors such as climate, diet and migration.
“Part of that is looking for genetic traits that might have been beneficial to humans in the past during early epidemics,” he said. “There is no doubt that we can learn something from this about how we manage contemporary diseases and other outbreaks.”
Skoglund’s team sourced samples from archaeological excavations across the country or from museums with existing collections. His favorite bones to sequence are those found in our inner ear: “These bones are particularly good at preserving DNA because they are the least susceptible to microbial invasion and other factors that can cause DNA to degrade,” he explained.
The bones are ground up and run through a sequencing machine in much the same way as any DNA sample. But ancient DNA required “professional protocols—modern DNA has long stretches that are largely intact, whereas ancient DNA, on average, only gets about 35 percent of the total base pairs.”
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