Dog Family Tree Shows History Of Canine Diversity

Dogs are man's best friend -- in more ways than one. While it is difficult to map the different dog breeds and how they came to be, it seems that a new study regarding canine genomes can help with research on human diseases.

In a study published in Cell Reports, scientists examined the genomes of 1,346 dogs to create a diverse map for tracing the relationship between their different breeds. The said map showed the types of dogs people crossed to create the ones that they now know. The study revealed dogs that perform similar fuctions do not necessarily share the same origins. In fact, analysis showed that an ancient type of dog may have even arrived in the Americas long before Christopher Columbus "discovered" the New World.

Science News noted that the study discovered several new things about man's best friend. Among these discoveries are the following:

DNA from hybrid dogs are backed up in historical records. For instance, genetic backtracking indicated that mixing bulldogs and terriers started in Ireland between 1860 and 1870. This linked the breed to a dog-fighting fad that crossed breeds to make better dog fighters.

Geography played a role in dog breeding. Genetic diversity was apparent in herder dogs. But when humans shifted from hunting to farming, the herding dog breeds may have emerged independently in different areas. This explained why the United Kingdom and Mediterranean people use different herding tactics.

Big dogs were not bred to be large. European mastiffs and Mediterranean sheepdogs do not actually share recent DNA changes, which means that their size traits rose for different reasons. For instance, mastiffs used their size to intimidate humans, but sheepdogs used theirs to overpower animal predators. Their sizes, however, were suspected to be among the first traits that attracted human breeders in the first place.

So how can these findings help humans? Scientific American noted that dogs and humans can suffer from similar conditions, such as epilepsy. Humans have hundreds of genes that can influence such illness. But because dogs are normally genetically isolated, scientists can look at the genes individually for a more efficient study.