Origin of the domestic dog that was the most divergent group. The study found that the skulls of the "Goyet dog" and the "Altai dog" had some dog-like characteristics and proposed that the may have represented an aborted domestication episode. If so, there may have been originally more than one ancient domestication event for dogs as there was for domestic pigs. One theory is that domestication occurred during one of the five cold Heinrich events that occurred after the arrival of humans in West Europe 37 000, 29 000, 23 000, 16 500 and 12 000 YBP. The theory is that the extreme cold during
Origin of the domestic dog the same time and in other cases at different times, with different wolf subspecies producing different dog lineages. Therefore, the number of dog domestication events is not known. A maternal mDNA study shows that dogs fall within 4 clades, indicating that dogs are derived from 4 separate lineages and that there was no single domestication event. A 2018 domestication study looked at the reasons why the archeological record that is based on the dating of fossil remains often differed from the genetic record contained within the cells of living species. The study concluded that our inability to date domestication is