Dogs, a man’s best friend, were not always like that. They once were wolves, claims a new study that has looked at the first instance of domestication of the animal.
Researchers at the Francis Crick Institute have found that the ancestry of dogs can be traced to at least two populations of ancient wolves and the domestication likely happened during the Ice Age, at least 15,000 years ago. However, they are yet to find evidence of whether it occurred in one single location or in multiple places.
In a study published in the journal Nature, researchers looked at the DNA of 72 ancient wolves spanning the last 1,00,000 years from Europe, Siberia and North America. They found that dogs are overall more closely related to ancient wolves from eastern Eurasia than to those from western Eurasia, suggesting a domestication process in the east.
“We also found that dogs in the Near East and Africa derive up to half of their ancestry from a distinct population related to modern southwest Eurasian wolves, reflecting either an independent domestication process or admixture from local wolves,” researchers said in the paper.
The DNA was extracted from previously excavated ancient wolves, with archaeologists from 38 institutions in 16 different countries contributing to the study. The study included a full, perfectly preserved head from a Siberian wolf that lived 32,000 years ago with nine different ancient DNA labs then collaborated on generating DNA sequence data.
Analysis of the DNA sequences revealed that both early and modern dogs are more genetically similar to ancient wolves in Asia than those in Europe.
The team also found evidence that two separate populations of wolves contributed DNA to dogs. Early dogs from north-eastern Europe, Siberia and the Americas appear to have a single, shared origin from the eastern source. But early dogs from the Middle East, Africa and southern Europe appear to have some ancestry from another source related to wolves in the Middle East, in addition to the eastern source.
“Through this project we have greatly increased the number of sequenced ancient wolf genomes, allowing us to create a detailed picture of wolf ancestry over time, including around the time of dog origins,” Anders Bergström, co-first author of the study said in a statement.
The team used 72 ancient wolf genomes that spanned over 30,000 generations to look back and build a timeline of how wolf DNA has changed, tracing natural selection in action. They observed that over a period of around 10,000 years, one gene variant went from being very rare to being present in every wolf, and is still present in all wolves and dogs today.
“This is the first-time scientists have directly tracked natural selection in a large animal over a time-scale of 100,000 years, seeing evolution play out in real time rather than trying to reconstruct it from DNA today,” Pontus Skoglund, senior author and group leader of the Ancient Genomics lab said.