Cavalier King Charles spaniels carry a high number of harmful genes

By Krista Charles

Dog breeding has produced canines in a variety of shapes and sizes, but has also led to a build-up of harmful mutations in certain breeds. A new study suggests that cavalier King Charles spaniels carry a particularly high level of mutations, including variants linked to a heart condition called myxomatous mitral valve disease.

Erik Axelsson at Uppsala University in Sweden and his colleagues compared the sequenced genomes of 20 individual dogs from eight popular dog breeds, such as German shepherds and golden retrievers, and found that …