A duplication on canine chromosome 18 is behind Siberian huskies’ blue eyes, according to a study published in PLOS Genetics by Adam Boyko, PhD, founder and CEO of Embark Veterinary, and Aaron Sams, PhD, senior scientist at Embark Veterinary Inc. and colleagues.
According to the authors, this is the first consumer genomics study conducted in a nonhuman model and the largest canine genome-wide association study to date (the DNA of 6,000 dogs was tested).
Embark Veterinary is a DNA research company with offices in Boston and Ithaca, N.Y., and a research partner of the Cornell University College of Veterinary Medicine.
Boyko, Sams, and colleagues used a diverse panel of 6,070 genetically tested dogs from owners that contributed phenotype data via web-based surveys and photo uploads. They found that a 98.6-kilobase duplication on chromosome 18 near the ALX4 gene, which plays an important role in mammalian eye development, was strongly associated with variation in blue eye color, primarily in Siberian huskies but also in nonmerle Australian shepherds.
One copy of the variant was enough to cause blue eyes, or heterochromia. However, some dogs with the variant did not have blue eyes, so other genetic or environmental factors are still involved. Future studies may lead to the discovery of a novel pathway by which blue eyes develop in mammals.
“Using genetic data from the pets of our customers, combined with eye colors reported by customers for those same animals, we have discovered a genetic duplication that is strongly associated with blue eye color,” said Sams. “This study demonstrates the power of the approach that Embark is taking towards improving canine health. In a single year, we collected enough data to conduct the largest canine study of its kind. Embark is currently pursuing similar research projects in a range of morphological and health-related traits and we hope to continue to use our platform to move canine genetics and health forward in a very real way.”