A fascinating story.
I am a member of AAAS, the American Association for the Advancement of Science, and pulled a story from their Science journal and to my amazement found that I did this nearly a year ago.
The article, by Linda Goodman and Elinor K. Karlsson, is unavailable for complete republishing owing to copyright.
But on the AAAS website there is a summary, as follows:
Few traces remain of the domesticated dogs that populated the Americas before the arrival of Europeans in the 15th century. On page 81 of this issue, Ní Leathlobhair et al. (1) shed light on the origins of the elusive precontact dog population through genetic analysis of ancient and modern dogs. Building on earlier work, they show that American dogs alive today have almost no ancestry from precontact dogs, a monophyletic lineage descended from Arctic dogs that accompanied human migrations from Asia. Instead, the authors found that their closest remaining relative is a global transmissible cancer carrying the DNA of a long-deceased dog. It remains unclear why precontact dogs survived and thrived for thousands of years in the Americas only to swiftly and almost completely disappear with the arrival of Europeans.
From the article I would add:
It is unclear why there is so little evidence today of this thriving precontact dog population. Early European colonists may have discouraged the sale and breeding of native dogs, or even actively persecuted them (10). Yet, cultural preferences alone seem insufficient to explain their rapid decline. Most dogs worldwide are free-breeding scavengers, with minimal human control and high reproductive rates (11); native American dogs were likely similar.
There is a chart in the same article that shows the first human sites in the Americas were about 15,000 years ago with the oldest dog remains, also in America, being about 10,000 years ago.