DNA study of famous US sled dog shows what made him so tough

A statue is dedicated to him in New York’s Central Park, and a film has even been made about him: a sled dog named Balto. Now, 90 years after his death, he’s the focus of a DNA study to see what made the pooch so famously tough.

In 1925, this Siberian husky was part of an Alaskan expedition called Serum Run, whose goal was to bring life-saving medicines to young people in the remote town of Nome at risk of diphtheria.

The mission, in terrible snowstorm conditions, involved a number of sled dog teams transporting the anti-toxin squadron out of the city of Anchorage. Balto led the dog team that completed the final leg of the grueling journey.

The dog died in 1933 and his mounted body has been on display at the Cleveland Museum of Natural History ever since.

“Balto’s fame and the fact that he was stuffed gave us this cool opportunity 100 years later to see what this population of sled dogs would have looked like genetically and to compare him to modern dogs,” said Katherine Moon, a postdoctoral researcher at the university from California, Santa Cruz and lead author of the study.

It was published in the magazine on Thursday Science.

Her team took skin samples from the dog’s abdomen and reconstructed its genome – the full set of genes in an organism.

They compared this genetic material to that of 680 contemporary dogs from 135 breeds.

Contrary to a legend that claimed Balto was half-wolf – as suggested in an animated Universal Pictures film released in 1995 – this analysis found no evidence that he had wolf blood.

It turned out that Balto had ancestry with today’s Siberian huskies and the sled dogs of Alaska and Greenland.

Zoom’s team also compared Balto’s genes to the genomes of 240 other mammalian species as part of an international effort called the Zoonomia Project.

In this way, the researchers were able to determine which DNA fragments were common to all these species and therefore have not changed over millions of years of evolution.

This stability suggests that these stretches of DNA are linked to important functions in the animal, and that mutations there could be dangerous.

The conclusion of the research was that Balto had fewer potentially dangerous mutations than modern dog breeds, suggesting he was healthier.

“Balto had variants in genes related to things like weight, coordination, joint formation and skin thickness that you would expect from a dog bred in this environment,” Moon wrote in a statement.

© 2023 AFP