A new study has found that dog breeding has led cavalier King Charles spaniels to carry a high level of genetic mutations, including ones associated with a heart condition, New Scientist reports.
An Uppsala University-led team of researchers sequenced the genomes of 20 dogs from eight different, common dog breeds to examine their mutational loads. As they report in PLOS Genetics, they found that cavalier King Charles spaniels harbor more potentially deleterious alterations than the other breeds analyzed, which included beagles, poodles, and German shepherds, among others. This finding suggests, according to the researchers, that the intense breeding pressure on cavalier King Charles spaniels contributed to this high mutational load.
The researchers additionally identified genetic risk variants associated with myxomatous mitral valve disease among cavalier King Charles spaniels. This heart condition, they note, is a common reason cavalier King Charles spaniels' owners seek veterinary care. The researchers tied variants that regulate the NEBL gene in papillary muscles to myxomatous mitral valve disease, indicating that changes to papillary muscle integrity could influence disease development.
First author Erik Axelsson, an Uppsala researcher, tells the Daily Mail that other dog breeds could also harbor high levels of genetic mutations. "Future research will probably answer this question and potentially provide a more precise answer as to why we see these differences," he adds there.