Despite not having the title of Man’s best friend, cats are twice as genetically similar to humans as dogs are.
The age-old debate over whether humans are more like cats or dogs has—and cat lovers will probably like the result.
Humans seem to be genetically closer to cats than dogs when scientists examine the way DNA is structured and organized within chromosomes. Although humans, cats and dogs share distant mammalian ancestry, researchers say the finer details of genome organization put felines ahead in comparison.
From a broader evolutionary perspective, however, the distinction is less drastic. You humans belong to the primate family treewhile cats and dogs are part of the order Carnivora. Scientists estimate that primates and carnivores diverged from a common ancestor approximately 90 to 95 million years ago. In simple evolutionary terms, humans are therefore approximately equally related to both species.
The difference arises when researchers focus on the structure of chromosomes rather than general DNA sequences. Comparative genomic studies show that dogs have suffered extensive chromosomal rearrangements throughout their evolutionary history, while cats have maintained a genomic structure more similar to humans.
“In terms of the way genes are organized within chromosomes, humans and cats are twice as similar than humans and dogs”, explained comparative geneticist William Murphy, from Texas A&M University, to .
The researchers say these similarities are more than a biological curiosity. The way genes are organized affects how they are turned on or suppressed, meaning that genes cats can serve as particularly valuable models for the study of human diseases and genetic regulation.
Recent studies have already identified important overlaps between feline and human diseases. One example involves the gene FBXW7which researchers found mutated in more than half of feline mammary tumors examined in one study. In humans, mutations in the same gene are associated with worse prognoses in breast cancer patients.
Scientists have also observed similarities between cats and humans in conditions such as polycystic kidney diseasefurther increasing interest in feline genetics as a tool for medical research.
Dogs continue to play an important role in scientific studies, especially in research related to Alzheimer’s disease, epilepsy and cardiovascular disease. However, experts note that cats have historically received less attention in genomic research, in part because the feline genome mapping began later and in part because cats are notoriously difficult to use as research subjects.
The findings are unlikely to resolve the cultural rivalry between dog and cat enthusiasts anytime soon. Still, the growing body of genetic evidence offers cat owners new arguments in the age-old dispute.
