The impact of an ancient gene variant on coat colors in modern dog breeds has been characterized by a team of researchers at Wisdom Health Genetics. The findings, which were supported by citizen science, are published inCanine Medicine and Genetics.

What do the coat colors of prehistoric and modern dogs have in common? The most recent connection is a newly characterized genetic variant: ancient red. The ancient red variant (R301C) was first identified in 10,000-year-old dog DNA samples and is thought to be one of the earliest mutations captured by dog domestication.

Our research team conducted a large genotype screening effort of thousands of DNA samples submitted for commercial genetic panel testing to determine the frequency and distribution of an ancient gene variant—the R301C variant located in the Melanocortin 1 Receptor gene (MC1R)—in today’s dog population. The study found the R301C variant retained in 35 breeds, with a frequency of 1.5% across the researched population. Hound breeds, like the Drever and English Foxhound, and Spitz breeds, like the Alaskan Malamute, Alaskan Klee Kai, and Siberian Husky, most commonly showed the ancient R301C variant at theMC1Rgene.

TheMC1Rgene is important because it determines a dog’s coat color by producing a key signaling molecule on melanocytes, including enzymes responsible for the synthesis of eumelanin (dark) pigment. If theMC1Rfunction is lost, only pheomelanin (light) pigment can be produced. FiveMC1R更改功能的变体与狗中的深色面膜，灰色和隐性红色外套颜色表型相关，并且正如我们发现的那样，有第六个变体的R301c的R301cMC1Rthat also widely impacts coat color.

Understanding the far-reaching impact of a prehistoric variant

为了表征古代R301C变体对狗外套颜色表型的影响，我们获得了基因型的组合，用于其他已知的外套颜色变体Canine Beta-Defensin 103 (CBD103)andAgouti Signaling Protein (ASIP). We then compared the coat color genotype combinations to the dog’s appearance or phenotype thanks to owners turned citizen scientists who submitted photos of their dogs.

由于在确定狗的外套颜色方面有各种基因，因此我们首先搜索了R301c在一个品种Tamaskan Dog中会产生的任何外套颜色影响。We found a significant association between the ancient R301C variant to a coat color patterning referred to as “domino”, a phenotype encompassing striking facial markings with a receded eumelanin line forming a widow’s peak in the forehead.The domino patterning is common in Alaskan Malamute, Alaskan Klee Kai, Finnish Lapphund, and Siberian Husky, and now our findings strongly suggest that we have a genetic cause for this phenotype.

跨品种和个体的表型分析还表明，指定为古代红色（EA）的R301C变体不仅会导致多米诺骨牌图案。它还导致多种表型的更多苯烷蛋白（黄红）和更少的eumelanin（黑棕色）色素沉着。

我们的发现表明，R301C变体是狗先前未描述的部分功能丧失变体。这将使我们能够了解有关之间关系的更多信息MC1R,CBD103,andASIP, the main genes contributing to coat colors in dogs. The reduced MC1R variant: ancient red (eA) prevents the expression of solid black coat color, having the reverse effect on CDB103 and ASIP gene interaction.

Impact of Citizen Science

公民科学在这项研究中发挥了至关重要的作用。狗的照片帮助我们了解了哪些基因是不同的外套颜色表型。如果没有提供狗照片的所有者的投入，就无法发现古代红色变种。

Thanks to a robust DNA database—with millions of dogs tested worldwide—the research team behind the Wisdom Panel™ dog DNA test is able to analyze large sample sizes to find these genetic connection points across time and space.

Citizen science further enhances the potential of these studies, making it especially exciting for the field of companion animal genetics; pet owners’ contributions can not only help research teams like ours make new discoveries but also help make the world better for their pets.