Dogs are descended from the gray wolf and their domestication occurred at least 15,000 years ago, but where it occurred is still unknown. A new study investigates this mystery, indicating that their ancestors can be traced back to two groups of Ice Age wolves.
The research led by the Francis Crick Institute (UK), with Spanish participation and published in Nature, analyzed the genomes of 72 ancient wolves, from the last 100,000 years from Europe, Siberia and North America. The Doñana Biological Station (Huelva) contributed various samples.
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The international team of geneticists and archaeologists from 16 countries used the remains of ancient wolves that had previously been excavated, andAmong them is a complete and completely preserved head of a Siberian wolf that lived 32,000 years ago, for DNA sequencing data.
Primitive and modern dogs are genetically more similar to the wolves of ancient Asia than to those of Europe, indicating domestication somewhere in the East. But in addition to this, the researchers found evidence that two distinct groups of wolves contributed to the formation of the dogs’ DNA.
Thus, it appears that the first dogs from Northeastern Europe, Siberia and America “have one ancestry in common with the eastern source,” while the dogs of the Middle East, Africa and southern Europe would have an ancestry from another source related to eastern wolves. East plus East.
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Scientists point to two possible explanations for this dual origin, although at the moment “it is not possible to determine which of these two hypotheses occurred.” One explanation is that wolves have been domesticated more than once and that different populations have mixed. Another possibility is that domestication occurred only once and that the dual origin is due to the intermingling of these early dogs with wild wolves.
The genomes of 72 ancient wolves that were analyzed span some 30,000 generations, making it possible to look back and build a timeline of how wolf DNA changed, tracing natural selection in action. In this way, they observed that around 10,000 years ago, the genetic variant went from being very rare to being present in all wolves, and is still present today in both wolves and dogs.
The variant affects the IFT88 gene, which is involved in the development of the bones of the skull and jaw, and its spread is likely due to the change in available prey during the Ice Age, which gives an advantage to wolves with a certain head shape, but the gene can also have other unknown functions.
This is the first time that natural selection has been directly followed in a large animal over 100,000 years, noted study lead author Pontus Skoglund, “seeing evolution unfold in real time rather than trying to reconstruct it from current DNA.”
The team continues to search for closer ancestors of dogs, which can more accurately reveal where domestication occurred, and are now focusing on genomes from other sites not included in this study, including southern regions.
The Doñana Biological Station will continue to collaborate, particularly providing and analyzing Paleolithic and Chalcolithic samples of wolves and dogs from Andalusia and elsewhere in southern Spain and Europe. These are “particularly important specimens, as the oldest wolf fossils were found in the southern regions of Europe,” explained Jennifer Leonard, a researcher at CSIC’s Doñana Biological Station.
The problem is that “it is very difficult to get ancient DNA from these bones because the climate of Andalusia favors the degradation of genetic material.” However, this cooperation will be important for understanding the place of wolves and Andalusian dogs in prehistoric times.
EFE
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