The Intimate Bond Read Online Free Page A

present, the Bonn-Oberkassel beast is the earliest known and, lying alongside a human couple, suggests an intimate human-animal relationship, at minimum one of companionship. By fourteen thousand years ago, dogs begin to turn up in other places, among them, settlements in the Dnieper River Basin on the Central Russian Plain. Two nearly complete skulls are about the same size as those of modern-day Great Danes, large beasts that could possibly have been wolves held in captivity, or even wolf-dogs. There are other dog finds from the Ukraine, but what is striking is that the size of dog bones falls sharply after fifteen thousand years ago, especially among specimens from Southwest Asia dating to around nine thousand to ten thousand years ago, by which time domesticated dogs were commonplace and significantly smaller than wolves.
    Eleven Thousand Years of STDs, Canine Style
    Dogs suffer from a transmittable genital cancer, a sexually transmitted disease (STD) that causes bleeding genitals or forms grotesque tumors in canines wherever they live. This contagious cancer first appeared in a dog that lived about eleven thousand years ago. Unlike other cancers, which die with the patient, this sexually transmitted cancer passed to other dogs during the victim’s mating activities while it was still alive. A team of researchers sequenced this cancer genome, which carries about two million mutations, far more than in most human cancers, which have between a thousand and five thousand. 3 They used an infected Australian Aboriginal camp dog and a spaniel from Brazil, two beasts separated by more than sixteen thousand kilometers (ten thousand miles). The genetic makeup of the tumors from both animals was remarkably similar. By using a single mutation, known to accumulate through time, they were able to estimate that the cancer first appeared about eleven thousand years ago, when agriculture was taking hold in Southwest Asia and the Ice Age was in full retreat. They also compared DNA from modern tumor cells to the genotypes of 1,106 coyotes, dogs, and wolves. They believe that the original cancer-carrying beast may have resembled an Alaskan malamute or husky, with a short gray-brown or black coat. The sex of the animal is unknown, but most likely it was a relatively inbred individual.
    Transmittable cancer is commonplace among today’s dogs, but it existed among a single isolated dog population until about five hundred years ago. Since then, the cancer has spread widely around the world, perhaps carried by dogs that accompanied ships on global voyages during the European Age of Discovery. The tumor mutation rates showed that the Australian and Brazilian dogs’ cancer cells separated about 460 years ago.
    Cancers, both in animals and in humans, arise when a single cell acquires mutations that cause it to produce more copies of itself. The cancer cells can then metastasize to other parts of the body. But for them to leave the bodies of their original hosts and spread to other individuals is very rare indeed. The only other known transmittable cancer is a fast-moving facial cancer found in a carnivorous marsupial, the Tasmanian devil, spread by biting.
    The unknown canine ancestor that hosted transmissible cancer has passed us a genome to help cancer researchers better understand the factors that drive the evolution of many types of cancer. Above all, these researchers have an opportunity to understand what processes cause cancers to become transmissible and that could, one day, arise in either animals or humans.
    We’ll never know why a man and a woman were buried with their dog fourteen thousand years ago, for the intangibles of the past vanish within generations. Was it a faithful companion, a protector, or a beast valued in the hunt? Was it killed to accompany its owners into the other world or did it die somewhat later? Once again, the archaeological record is silent. That it was cherished is a certainty, for the mourners