Two grants from the Agria and SKK Research Foundation, one to IL (19969) and one to RH (P2011-0021), provided funding for sampling of dogs. Elanco (previously Novartis Animal Health) influenced the choice of dog breeds sequenced in this study, participated in data analysis and edited and reviewed the manuscript. Reference: “The genetic consequences of dog breed formation-Accumulation of deleterious genetic variation and fixation of mutations associated with myxomatous mitral valve disease in cavalier King Charles spaniels” by Erik Axelsson, Ingrid Ljungvall, Priyasma Bhoumik, Laura Bas Conn, Eva Muren, Åsa Ohlsson, Lisbeth Høier Olsen, Karolina Engdahl, Ragnvi Hagman, Jeanette Hanson, Dmytro Kryvokhyzha, Mats Pettersson, Olivier Grenet, Jonathan Moggs, Alberto Del Rio-Espinola, Christian Epe, Bruce Taillon, Nilesh Tawari, Shrinivas Mane, Troy Hawkins, Åke Hedhammar, Philippe Gruet, Jens Häggström and Kerstin Lindblad-Toh, 2 September 2021, PLoS Genetics.įunding from Elanco (previously Novartis Animal Health) to KLT covered the generation of WGS data and parts of EA’s salary. In the Cavalier King Charles spaniel specifically, one or several of these mutations affect heart muscle protein NEBL and may predispose this breed to devastating heart disease.” The bottlenecks may have made the harmful genes more common in the cavalier King Charles spaniel genome before the dog achieved recognition as a breed in 1945.Īxelsson adds, “We find that recent breeding may have led to an accelerated accumulation of harmful mutations in certain dog breeds. These spaniels experienced several “bottlenecks” where only a small percentage of the population passed on their genes to the next generation. Records suggest that small spaniel-type dogs have existed for at least 1,000 years and were popular at royal courts for several hundred years throughout Asia and Europe, including at the court of King Charles II (1630-1685). The especially large number of potentially harmful genes in the genomes of cavalier King Charles spaniels, compared to other dogs, likely resulted from its breeding history. The findings offer a potential explanation for why the cavalier King Charles spaniel is predisposed to develop the disease. They identified two genetic variants linked to the disease, which appear to regulate a gene that codes for a common protein in heart muscle. In this condition, the mitral valve in the heart degenerates, allowing blood to leak from the left ventricle back into the left atrium. The researchers also looked for genetic variants in the cavalier King Charles spaniel genomes linked to MMVD. Credit: Måns Engelbrektsson, Swedish Kennel Club, CC-BY 4.0 Comparisons of dachshunds with and without signs of heart disease were used to help identify mutations that potentially predispose cavalier King Charles spaniels to develop MMVD.