Evolution of Cats
Pankaj Singh
| 01-04-2024
· Animal Team
As household pets, cats can alleviate people's psychological stress and fulfill their emotional needs.
Moreover, in terms of their ability to catch mice, they contribute significantly to saving substantial economic losses for humans annually.
Cat culture emerged at the beginning of human domestication of cats, during which cats were revered as "sacred animals," in early Egyptian art, they held a dual identity as both sun and moon gods.
Humans and cats have lived together for at least 9000 years, but little is known about how wild cats roaming outdoors transformed into the cats dominating our homes.
How were domestic cats domesticated?
Domestication refers to the process whereby one species gradually becomes adapted to and controlled by another species for its purposes.
For humans, domestication marks a significant advancement. Examples include the domestication of wheat, domestic animals, and so forth, which have allowed humans to live in abundance, signifying progress in human civilization.
Researchers have compared the genomes of domestic cats, wild cats, and several other mammalian species. The results revealed changes in genes related to memory, fear regulation, and stimulus-reward learning in domestic cats compared to wild cats. Additionally, variations were found in genes related to lipid metabolism in domestic cats.
Archaeological evidence indicates that humans began living with these adorable feline companions around 9500 years ago in Cyprus. Previous studies have focused on differences between cat breeds, the phylogenetic origins of domestic cats, and the degree of genetic introgression between domestic and wild cats.
However, much remains unknown about how the domestication process altered the genetic characteristics of modern domestic cats and how they differ from other domesticated animals. Therefore, researchers have sought to identify molecular footprints left by domestication through the analysis and comparison of cat genomes.
Domestication process leaves genetic footprints
Initially, researchers sequenced the entire genome of an Abyssinian cat to identify functional genes.
They then compared these genes with similar genes in tigers, cattle, and humans to identify genes subject to positive selection (preserved because they benefit the species) in carnivores, felids, and domestic cats. So, where do these genes play a crucial role in cats?
Researchers found six genes that can enhance cats' auditory sensitivity, with mutations leading to deafness. Moreover, some genes improve visual sensitivity, which is crucial for cats, primarily crepuscular hunters. Corresponding gene mutations in humans are associated with various visual disorders.
Experimental results also showed changes in genes related to lipid metabolism in cats. Unlike most carnivores, cats are obligate carnivores and cannot synthesize certain essential amino acids, possibly leading to the evolution of different lipid metabolism pathways. Additionally, although cats consume large amounts of fatty acids, they do not affect blood lipid levels, possibly leading to cardiovascular disease in humans.
To understand which genes make cats unique, researchers identified the fastest evolving genes in domestic cats through phylogenetic tree analysis, including two chemosensory gene families that control the expression of odorant receptors (Or) and vomeronasal receptors (V1r). It was found that cats have fewer Or genes than dogs, while they have more V1r genes.
Researchers explained, "Odorant receptors detect volatile odor molecules, while vomeronasal receptors are responsible for detecting pheromones. Since wild cats typically live solitary lives, vomeronasal receptors play a crucial role in interpreting social cues, such as reproduction and hunting.
Therefore, these genes are more critical for solitary cats like domestic cats than for more social canines. Domestic cats retain these genes and behaviors from wild cats because the history of cat domestication is shorter than that of dogs.”
Researchers also hope to continue collecting genetic sequence data from various breeds of domestic and wild cats and address questions about the timing and origins of cat domestication. They are also interested in other genetic characteristics of domestic cats, such as differences in facial and tail morphology, diversity in fur color patterns, and diseases similar to those in humans found in felids.