Pet Cloning: Where We Are Today
Increasing numbers of pet owners are having their beloved dogs and cats cloned. Here’s what veterinary teams need to know.
“This topic evokes a lot of questions,” Kerry Ryan, DVM, animal care director for ViaGen Pets & Equine, said at the outset of her general session lecture on cloning in dogs and cats at the 2018 Atlantic Coast Veterinary Conference®. The lecture’s purpose, she said, was to explain what genetic preservation is, provide a basic understanding of how cloning works, and make veterinary professionals aware of the fact that “we are actually doing this and it is working really well.” During her lecture, Dr. Ryan also highlighted the important role veterinary teams play in the cloning process.
Dolly the sheep was cloned 22 years ago, in 1996, and ViaGen Pets has been cloning horses and livestock for 17 years. The company began cloning pet dogs and cats in 2015. “We’re the only company in the world that is cloning cats for pet owners and the only company in the United States that is cloning pet dogs,” Dr. Ryan said. The company has also cloned cattle, pigs, sheep, goats, and white-tailed deer.
By doing a single study to help establish a non-animal based model, officials with the FDA are aiming to replace much of the need to use dogs in future trials with new informatics tools.
“The human—animal bond is a pretty strong thing,” Dr. Ryan said. “Our pets truly are a part of the family, and people want to have a piece of their pets around forever.” ViaGen Pets works with owners to help them understand that the cloned pet will not be the same as the original pet in every way.
“The clients interested in cloning tend to be your highest-end clients,” Dr. Ryan said. And she is not necessarily referring to the wealthiest clients. “It’s those clients who love their pets the most, who are the most compliant with your recommendations for regu- lar office visits, screenings, and year-round parasite prevention,” she noted.
Cloning is also getting increased interest from groups that work with military and working dogs. One of ViaGen Pets’ clients is a retired Navy SEAL who breeds and trains high-end working and police dogs. He has been working with the company for about 3 years. His goal is to improve training success rates in the puppies he works with. “The evidence is anecdotal at this point,” Dr. Ryan said, “but it does seem as if the cloned puppies are training at a higher success rate than conventionally bred litters—even conventionally bred litters where the best working dogs are bred together.” The cloned puppies are also training faster, she said, going through training start- ing at age 9 months compared with age 18 months for conventionally bred dogs. “That is a remarkable difference,” she said.
- To Clone or Not to Clone
The First Step: Genetic Preservation
Another name for DNA storage, genetic preservation is the first step in the cloning process. “The process typically begins when a client orders a genetic pres- ervation kit through our website,” Dr. Ryan said. To get the fibroblast cells needed for cloning, a skin biopsy sample must be obtained from the pet’s primary care veterinarian. The samples are shipped to ViaGen Pets’ lab in Cedar Park, Texas, where they are cryopreserved and cultured for cloning.
“The tissue can be stored indefinitely,” Dr. Ryan said, “and many pet owners are opting for genetic preservation simply to have the option to clone their beloved pet if they so choose down the road.” She recounted one client whose German shepherd was cloned last year but who was forward-thinking enough to have had the dog’s DNA preserved in 1999—just a few years after Dolly was cloned. “The dog died more than a decade ago, and the cloned pup is now 6 months old,” she said, “so it’s pretty cool for these owners to have a piece of their beloved dog back with them after so much time.”
Obtaining the Biopsy
There is growing interest in genetic preservation among pet owners, according to Dr. Ryan. ViaGen Pets has preserved cell lines for thousands of animals to date. “And this is a service that can easily be added on during a dental procedure or other elec- tive surgery,” she said. Samples can be taken from animals of any age.
Any sedation or anesthetic protocol can be used to obtain the skin biopsy, including general anesthesia, Dr. Ryan said. Local anesthetic can be injected into the biopsy area. A 4-mm punch biopsy (which is just a bit smaller than a pencil eraser) is collected using asep- tic technique, typically from the ventral abdomen or the inner thigh. At least 2 and preferably 4 samples are needed to collect the appropriate number of cells.
Areas with apparent skin contamination should be avoided. Ideally, samples are taken from 2 distinct areas in case unseen skin contaminants are present.
Sampling cells up to 5 days postmortem can be successful as well if the samples are refrigerated, not frozen, Dr. Ryan said. “Freezing denatures DNA very quickly,” she emphasized, “and although we have done genetic preservation using frozen tissue, the likelihood of success is much lower.” Standard aseptic technique remains important, even with deceased pets.
More tissue is required when sampling from deceased pets; ViaGen Pets recommends excisional biopsies that are about 2 by 2 cm taken from at least 2 distinct sites. “Oddly enough, the skin on the ear has been very successful for us with postmortem sampling,” Dr. Ryan said.
Time is of the essence with an unexpected death, she said. Rather than waiting for a kit to be mailed, the veterinarian can collect the samples in individual plain red-top tubes with sterile saline. Samples should be refrigerated until they are packaged for shipment.
The topic of genetic preservation often comes up around the time of euthanasia, and this is the time when sampling is often completed. “You can eutha- nize a pet prior to obtaining samples,” Dr. Ryan said.
The Cloning Process
“Cloning is the act of creating a genetic identical twin that is born at a later date,” Dr. Ryan said. First, one of the original pet’s cells is transferred into a donor animal’s oocyte, from which the DNA has been removed. During ViaGen Pet’s patented electrofusion process, the egg and cell join together to create a viable embryo, and multiple embryos are then placed in the uterus of a surrogate mother of the same species (but not necessarily of the same breed). After a typical gestation period (about 60 days for dogs and cats), the surrogate will give birth to 1 or more cloned pets. “We are using the exact same DNA from the original pet; no genetic manipulation or modification is involved,” she said.
The cloned puppies and kittens remain in ViaGen Pets’ care until weaning is complete at 8 to 12 weeks of age. The pet then goes home to its eager family.
THE VETERINARIAN’S ROLE
“The demand for cloning has increased dramatically in the past year,” Dr. Ryan said, “so it would behoove veterinary practices to gain a better understanding of what the procedure entails so they can field the ques- tions that will inevitably come from clients. Practices can register with ViaGen Pets’ Veterinarian Network to state that they know what the procedure involves and are willing to participate in the process. “Adding genetic preservation as a service has been a practice builder for some veterinary hospitals,” she said. To be included in the network, a practice must register so pet owners interested in pursuing cloning can find a knowledgeable veterinarian in their area with whom to discuss the process.
Veterinarians who have questions about the cloning process can reach out directly to Dr. Ryan.
How much does it cost to clone a dog or a cat?ViaGen Pets’ fee to the client for genetic preservation is $1600, with an annual storage fee of $150 after the first year. In addition, veterinary practices charge the client for their expertise in collecting the biopsy samples. Beyond these initial charges, cloning a dog costs $50,000; a cat, $25,000; and a horse, $85,000.Is there a wait list?There are a few hundred cloned dogs out and about in the world, and there is a wait list. The current wait list to start the cloning process in dogs is about 2 months. For cats, the wait list is about 6 months.Are cloned dogs and cats healthy?There are misperceptions about the health of cloned animals, but their potential for good health is the same as for any conventionally bred puppy or kitten. Likewise, the potential life span of a cloned animal is the same as for a conventionally bred animal.Is a cloned animal phenotypically identical to the original pet?Although many people assume that because the cloned animal is a genetic identical twin it will look exactly like the original, there may be slight differences in appearance. This is much like human identical twins, who look similar but sometimes have subtle differences in appearance such as freckles and birthmarks in different areas. This is because the location of pigment deposits in fetal development is random. Cloning a white dog with black spots will result in a second white dog with black spots, but exactly where those spots or markings end up is variable. Sometimes the animals look shockingly similar to one another, and sometimes there are variations.Do cloned pets have a personality similar to the original pet’s?Personality is determined by a combination of factors, and there is no guarantee that a cloned animal will have the same personality as the original animal. The feedback from ViaGen Pets clients, however, has been that the personalities of cloned dogs and cats are very similar to those of the original pets. Results of human twin studies show that their temperament and other personality characteristics are quite similar, even among twins who were raised apart. The same can be expected for cloned pets.Are cloned animals able to reproduce?Yes. They are born sexually intact, and they age just as any conventionally bred animal ages.Can you clone a cloned animal?Yes. A cloned animal (and its future offspring) can be cloned.What happens if more than 1 puppy or kitten is born?More than 1 embryo is transferred to the surrogate dog during the cloning process to increase the likelihood of pregnancy. Typical litter size is 1 or 2 animals, but occasionally there are more. When this occurs, the client may (and usually does) take all of the animals if desired. In the rare event that the client elects not to take home all of the puppies or kittens born, ViaGen Pets runs an internal adoption program to home the remaining animals.