In the winter of 1925, a magnificent sled dog named Balto captured the hearts of millions as he led a courageous team of 13 dogs through treacherous blizzards on a life-saving mission. Covering a grueling 674-mile dogsled relay, Balto and his pack braved unimaginable conditions to deliver vital medicine during a diphtheria outbreak in the remote Alaskan city of Nome.

Balto's heroic deeds earned him widespread acclaim, turning him into a legend. Books and movies immortalized his remarkable story, and today, visitors can still witness his incredible legacy at the Cleveland Museum of Natural History, where Balto's taxidermy mount stands proudly on display. But Balto's tale doesn't end there. In a groundbreaking scientific endeavor called Zoonomia, researchers have extracted DNA from a piece of Balto's preserved underbelly skin and sequenced his genome, unveiling astonishing insights into his genetic makeup.

The scientists discovered that Balto's genome contains unique gene variants that likely contributed to his ability to thrive in the harsh Alaskan environment during the legendary Serum Run. Balto, belonging to a population of working sled dogs in Alaska, exhibited a level of genetic diversity and health far surpassing that of modern canine breeds.

Katie Moon, a postdoctoral paleogenomics researcher at the Howard Hughes Medical Institute and co-lead author of the study published in the prestigious journal Science, expressed the significance of Balto's story, stating, "Balto personifies the strength of the bond between human and dog, and what that bond is capable of. Dogs not only offer comfort, support, and friendship to humans, but many are actively bred or trained to provide vital services. That bond between human and dog remains strong, 100 years after Balto's job was done."

During the diphtheria outbreak, when the port of Nome was cut off by ice, sled dogs became the only lifeline for delivering the much-needed antitoxin. Balto was among the courageous canines who participated in the relentless 127-hour relay, enduring bone-chilling temperatures as low as minus-50 degrees Fahrenheit (minus-45 degrees Celsius).

The study involved an analysis of Balto's genome alongside a vast dataset of 682 genomes from modern dogs and wolves, as well as 240 mammalian genomes, including humans. Astonishingly, Balto's genome revealed significantly lower rates of inbreeding and a reduced burden of rare and potentially harmful genetic variations compared to most modern dog breeds. It was also discovered that Balto shares ancestry with present-day Siberian huskies, Alaskan sled dogs, Greenland sled dogs, Vietnamese village dogs, and Tibetan mastiffs, without any discernible wolf lineage.

Born in 1919, Balto was part of a population of sled dogs imported from Siberia, although the study highlighted significant differences between these dogs and modern Siberian huskies. Balto, despite not possessing great speed, had a robust build built for strength, which disappointed his breeder, leading to him being neutered.

Balto's life after the Serum Run was a tale of both exploitation and redemption. After touring the United States on the vaudeville circuit for two years, he ended up in a Los Angeles dime museum, where he and his sled team companions were mistreated and put on display as a low-brow exhibition. However, fate intervened when a compassionate Cleveland businessman witnessed Balto's plight and arranged to purchase the dogs for $1,500. The local community in Cleveland rallied together to raise the funds, and in 1927, Balto and his fellow canines—Alaska Slim, Billy