When we think of bioengineering we think of modern labs staffed by white-coated scientists tinkering with the genomes of plants and animals. But the reality is that humans were manipulating nature for their own purposes thousands of years before even learning of the existence of DNA.
Now, a new study has revealed that some 4,500 years ago the ancient Mesopotamians were the first to create a hybrid animal, producing an entirely new beast by mating two different species.
Meet the kunga – a feisty little equid that is mentioned in cuneiform inscriptions, depicted in ancient Mesopotamian art and often found in monumental burials across the region.
But the origin and classification of this animal has remained a bit of a mystery. Morphologically, kunga skeletons don’t fit any other known species of wild or domesticated equid, so inquisitive minds have been wondering how exactly such an animal came to be.
Putting the ass in artificial evolution
The answer comes for a study published Friday in Science Advances for which researchers sequenced DNA from kunga bones found in a royal burial complex at Umm el-Marra, near Aleppo in today’s northern Syria. Possibly identified with the ancient city of Tuba, this was one of the oldest urban settlements in the ancient Near East. The city’s elite funerary complex dates to 2,600-2,200 B.C.E., and, in addition to the remains of ancient rulers, it also housed the complete skeletons of 25 male kungas, some of whom may have been sacrificed and buried with their masters.
The DNA in the skeletons was poorly preserved, as is often the case in the hot Levantine climes, explains Eva-Maria Geigl, a paleogeneticist from the University of Paris and France’s National Centre for Scientific Research. Still, the researchers managed to identify sequences in the Y chromosome of the kunga that are typical of the Syrian wild ass, also known as a hemippe, while the mitochondrial DNA contained genes that are found in domesticated donkeys.
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Since mitochondria are usually inherited from the mother and the Y chromosome from the father, the scientists concluded that the kunga was in fact a hybrid of a female donkey and a male hemippe. The latter is a now extinct subspecies of the Asian wild ass, or onager.
To further confirm their findings, Geigl and colleagues compared the DNA from Umm el-Marra to that found in an 11,000-year-old hemippe bone from the Neolithic site of Gobekli Tepe in Turkey as well as samples preserved from the last known members of the species, who died in captivity in a Vienna zoo in the early 20th century.
“So, we were able to write the genetic history of this now extinct species, the Syrian wild ass,” Geigl says. “And all the analyses confirmed that the equid burials from Umm el-Marra were 50 percent Syrian wild ass and 50 percent domestic donkey.”
This turns back the clock by 1,500 years on the earliest known human-made hybrid. Previously, the oldest known hybrid was a mule – the offspring of a male donkey and a female horse – found in central Anatolia and dated to around 1000 B.C.E, Geigl says.
But more than that, the discovery reveals a new side of the highly sophisticated Mesopotamian civilizations of the Early Bronze Age, the researchers say.
Like mules and other equid hybrids, kungas would have been sterile, explains Thierry Grange, another geneticist who participated in the study. This means that to produce every new generation, more hemippes had to be captured in the wild to be mated with donkeys. And this was not an easy task as the Syrian wild ass was faster than a horse, untamable and aggressive, Grange notes.
This certainly helped make kungas extremely expensive, fetching up to six times the price of a donkey, he notes. They became prized animals, often exchanged as gifts amongst the elites of the region’s city states, from Ur in today’s southern Iraq to Ebla in northeastern Syria.
Warhorses before horses
But why go to all this trouble to create a costly, sterile hybrid? We have to remember that this was a time before the introduction of domesticated horses. This equid was first tamed in the steppes of central Asia around 5,500 years ago, but only reached Mesopotamia, through the Caucasus and Anatolia, around 4,000 years ago, about half a millennium after the time of the kungas from Umm el-Marra.
On the other hand, donkeys, which descend from the African wild ass, had already been domesticated and were the beast of burden of choice during the Early Bronze Age.
But while donkeys make good workhorses, they make terrible warhorses, the researchers note. They are not particularly fast and, unlike horses, will not endanger themselves by, say, charging into an enemy army, just because their human masters bid them to do so. This has earned donkeys a reputation for being stubborn, although it may just mean that they are smarter than the average equid, Geigl quips.
So, kungas were probably the result of an attempt to create a beast fit for war, combining the robustness and malleability of the donkey with the aggression and speed of the wild hemippe, says Andrew Bennett, the lead researcher on the study.
“They had some limitations with the donkey and that’s what they came up with to overcome them,” he says.
The experiment appears to have been a wild success. While kungas were sometimes used in agriculture, they were mainly employed in conflicts to pull war wagons, lumbering four-wheeled contraptions that were the ancestor of the two-wheeled horse-drawn war chariot. Kungas pulling war wagons are depicted trampling their enemies in battle on the Standard of Ur, a decorated Sumerian artifact that also dates to around 2500 B.C.E.
Because of their price and function, kungas also became symbols of power in their own right, and were used as wedding presents and diplomatic gifts amongst Mesopotamian royalty, Bennett says.
Ultimately, the introduction of domesticated horses in Mesopotamia around 2000 B.C.E. spelled the end of the kunga breeding project, which is why these animals no longer exist. In the horse, humans found a fast, powerful equid who was brave enough to risk life and limb in battle, and could reproduce on its own. But until then, kungas were an efficient, if costly, alternative.
“This was an intentional program. They created a process to produce these hybrids, and this is an agricultural technique that is quite advanced for the time,” Geigl says. “This tells us less about the animals and much more about the humans in these societies.”
Perhaps, it also tells us something about humans in general. From kungas to nuclear weapons, it seems we are experts at finding pretty smart methods to control nature – and then weaponizing them into new ways of killing each other.