It is well known that domestic animals have higher cancer incidence than their wild counterparts, including domesticated trout, ducks, laboratory mice, Lipizzaner horses, domestic cats, boxers and other large dogs. Your paper, together with mine, suggests a novel explanation for this mystery.
Domestication causes the fixation of many mutant alleles that would otherwise be eliminated by purifying selection in the wild. These extra mutations in demestic animals weaken the epigenetic complexity of the domestic animals and make them more cancer prone than wild counterparts. There is an inverse relationship between genetic diversity/mutations and epigenetic complexity, as explained by my recent paper. (http://precedings.nature....)
Also, more recessive harm alleles may become manifested in artificially interbred domestic animals.
