The dog, or at that time the wolf, was one of the first animals that humans domesticated. When and where exactly that took place is a bit unclear. For example, there is a 33, 000-year-old find from what is now Siberia, which suggests that even then it was possible to have canine animals near human dwellings. The occurrence of dogs between 11, 000 and 12, 000 years is a bit better documented. Tombs used to be the place where people were buried together with dogs. Genetic analysis suggests that the dogs were domesticated at least 10, 000 years ago - either in the Middle East or East Asia, possibly in several places at the same time.
The dogs came with agriculture
Thus, the rapprochement between man and wolf falls into the time when man began to settle down and grow plants as food. And although it is unclear why exactly the wolves were domesticated, this consensus suggests a specific scenario: Perhaps the wolves were attracted by the rich food supply of the settlements, for example in the form of waste piles. Humans then began to use the roaming animals to hunt or guard, and to breed them in such a way that certain qualities increased in them and others, such as the aggressiveness, went back.
In the course of this process, the genome of the animals also changed, the researchers' analysis now shows - even though only in a few places does it actually differ from that of the wolf. They had genetic material from twelve wolves around the world compared to 60 dogs belonging to 14 different breeds. They found 36 regions that have changed in the dog compared to the wolf. Especially interesting: Among them were also ten genome sections, which enabled the dogs in the course of their Domestikation to digest strength better and faster. Above all, three enzymes, which are necessary for the splitting and conversion of starch, occur in the dog in significantly larger quantities and with higher activity than with the wolf. display
Concentrated feed instead of meat diet
This change was probably beneficial for the animals in their new habitat near humans, the researchers explain, as the supply of starchy food was relatively large there. Incidentally, a similar development took place in humans at the same time, so that one can speak here of a prime example of a parallel evolution in response to changed environmental conditions, the scientists conclude.
In the analysis of the dog genes, the scientists also found 27 other changes compared to the wolf. These areas primarily control brain function and the development of the nervous system. They find it likely that the changes in these regions underlie the behavioral changes that occurred to the wolves during adaptation to humans. The fact that the early dogs also changed physically could, according to the researchers also go back to the genes responsible for the development.
Original work of the researchers:
- Erik Axelsson (Uppsala University) et al .: Nature, online pre-release, doi: 10.1038 / nature11837