Cat Genome Project Holds Promise For Better Animal And Human Health
A cat may have only nine lives, but it has tens of thousands of genes that determine everything from physical traits to disease susceptibility. Researchers, including a team at Texas A&M University, will work to sequence the cat genome in hopes of finding keys to better health– not only for cats, but also humans.
William Murphy, a professor at Texas A&M’s Department of Veterinary Integrative Biosciences, in the College of Veterinary Medicine & Biomedical Sciences, and his team join researchers at the University of Missouri, Cornell University and the University of California-Davis in the “99 Lives Cat Whole Genome Sequencing Initiative,” to sequence the 20,000 genes in various breeds of cats.
The term “genome” refers to all of an organism’s genetic material.
Murphy, who specializes in mammalian comparative genomics, especially feline genetics, explains that sequencing a whole genome means identifying, in order, every DNA base in the genome. “Until very recently, most of the cat genome has remained un-deciphered,” Murphy notes. “Just recently, the complete genome of a single cat was determined.”
For the 99 cats project, as the name suggests, researchers will gather 99 additional cats of diverse breeds from a wide variety of geographic locations, take DNA samples and work to sequence their genomes. This will provide a large collection of sites in the cat genome that are likely to vary within and between individual cats of all breeds as well as non-breed cats throughout the world.
“To identify the genetic basis of traits of interest, we start by testing thousands of these genetic markers that are variable within the cat genome — locations that mark a location on a chromosome,” Murphy says. “To be able to determine which genes cause certain physical attributes, like body size for example, you have to find a specific marker that is consistently associated with a specific trait value or disease. When a marker like this is identified, we know somewhere on that chromosome, in the vicinity of that genetic marker, is the actual mutation that causes the disease. Then we use the genome sequence to identify the exact mutation that causes that trait or disease.”
Once they know what mutation causes a certain trait or disease, Murphy explains, a genetic test may be developed so that owners and breeders can have their cats tested and use the results for selective breeding. They may choose to breed for certain traits, such as fur or eye color, or to avoid breeding cats that carry a mutated version of the normal gene. Murphy says it may also be possible to develop new therapies to treat disease by targeting the right genetic mutation.
The first cat to be sequenced was Cinnamon, an Abyssinian, in 2007. But at that time only 60 percent of her DNA was determined, Murphy explains, whereas within the past two years researchers have sequenced 95 percent of her genome. “Today we have the ability to sequence many genomes at a fraction of the cost as compared to five years ago,” he notes.
Once the 99 subjects have been chosen, some of the DNA samples will derive from Murphy’s collection at Texas A&M. “It will take about six months, conservatively, to sequence and analyze each sample,” he says.
So what does the sequencing of the cat genome have to do with human health?
Murphy says cats and humans share several hundred pathologies, or causes and effects, of disease. “Often mutations in the same genes in both humans and cats cause the same disease, so if we can find a gene in a cat that causes a certain disease, we may be able to find the same in humans.”
He says diabetes, for example, is similar in cats and humans. “Cats are a good model for diabetes because they are sedentary and have similar risk factors that humans have.”
Other genetic diseases that have been studied in the cat include polycystic kidney disease, spinal muscular atrophy and cataracts.
Murphy explains the hope for human health, as with cats, is that new and better pharmaceuticals may be developed based on the knowledge gained from the project.
As the project progresses, researchers at the participating universities will share information with one another using a cloud-based website.