In a study examining the DNA of over 6,000 dogs, researchers at Embark Veterinary, Inc., Boston, Massachusetts, have identified that duplication of a part of canine chromosome 18 is strongly associated with blue eyes in Siberian Huskies.
Although two genetic variants are known to underlie blue eye color in some dogs, these do not explain the trait in some other dogs, like Siberian Huskies.
To address this gap in knowledge, Embark Veterinary researchers used a diverse panel of 6,070 genetically tested dogs with owners that contributed phenotype data via web-based surveys and photo uploads.
The team 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 non-merle Australian Shepherds.
One copy of the variant was enough to cause blue eyes or heterochromia (blue and brown eyes), although some dogs with the variant did not have blue eyes, so other genetic or environmental factors are still involved.
“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 Dr. Aaron Sams, co-lead author of the study.
“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.”
“We are 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.”
The results appear in the journal PLoS Genetics.
P.E. Deane-Coe et al. 2018. Direct-to-consumer DNA testing of 6,000 dogs reveals 98.6-kb duplication associated with blue eyes and heterochromia in Siberian Huskies. PLoS Genet 14 (10): e1007648; doi: 10.1371/journal.pgen.1007648