[Animals] This is the first hybrid of dog and fox, a unique genetic rarity

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This is the first hybrid of dog and fox, a unique genetic rarity
When first found, the animal was a mystery, as it displayed traits common to both dogs and foxes.

In 2021, you will be invited to travel to another place and find a place to receive food. Here they are, the principio pensaron that has been in a perro, then they die in a cuenta de que su comportamiento parecía mas el de un zorro. Laser genetics confirms what's going on that Dogxim era un híbrido de ambientes.

In 2021, a dog-like animal was taken to an animal rehabilitation center in southern Brazil after being hit by a car. Shortly after, veterinarians observed unusual behavior.

The animal looked and barked like a dog (although it featured long, pointed, fox-like ears), but it also climbed bushes, a behavior more typical of the local Pampas fox, and refused common dog food, preferring to eat rats.

The keepers began to wonder if it might not be a hybrid, a mix of a domestic dog and some wild canid from the area, so they contacted Thales geneticist Renato Ochotorena de Freitas and Rafael Kretschmer, from the Universidade Federal do Rio Grande do Sul, who last month published a study confirming that the animal was the first documented dog-fox in the world. The discovery excited and intrigued animal genetics experts.

"What a strange hybrid beast!" wrote Roland Kays, a biologist at North Carolina State University and the North Carolina Museum of Natural Sciences (United States), on X (formerly Twitter), along with a photo of the creature and a link to the study.

He added that, although hybridization between species is well known among more related animals, such as dogs and wolves, the domestic dog (Canis lupus familiaris) and the Pampas fox (Lycalopex gymnocerus) belong to "two genera separated by 6.7 million of years".

"This would be expected to be seen in trees, but not in vertebrates," says Loren Reiseberg, a geneticist at the University of British Columbia (Canada). "It's as if humans produced a viable hybrid with chimpanzees!"

Some animal hybrids are well known, such as the mule (a mix of a mare and a donkey), the hinny (a mix of a donkey and a horse) or the liger, a mix of a lion and a tiger, but the case of Brazil was somewhat different.

The creature, a female, was named "Dogxim," a cross between "dog" and graxaim do campo, the Portuguese name for the Pampas fox. And although it is the first, it may not be the last of its kind. Environmental changes could lead to more dog-fox hybrids in the future, a possibility that could have problematic consequences.

(Related: Thrushes, ligers, grolar bears and other oddities: How are animal hybrids produced?)

Discovering a hybrid
The first step to confirm the possibility that Dogxim was a hybrid was to determine the number of chromosomes in its cells. It had 76 in total, a clue that scientists could use to determine its species, since the same species usually has a fixed number of chromosomes. The maned wolf (Chrysocyon brachyurus) is the only canid in the region with 76 chromosomes, but its appearance and behavior ruled it out as a possible progenitor.

Scientists then reasoned that since a domestic dog has 39 chromosomes and a Pampas fox has 37, the resulting 76 chromosomes found in Dogxim could indicate "the first evidence of hybridization," Kretschmer says.

Geneticists next examined Dogxim's mitochondrial DNA (chromosomes inherited exclusively from his mother) and determined that they came from a Pampas fox. They then examined the nuclear DNA, which contains chromosomal information from both parents, and found a mix of dog and Pampas fox. The genetic tests were carried out over six months, during which Dogxim healed from her injuries from the accident and was transferred to an animal reserve.

Although foxes belong to the same biological family as wolves and dogs (Canidae), they do not belong to the same smaller group, the genus Canis. Instead, more than six million years ago, foxes diverged and became sufficiently differentiated to be considered the genus Vulpes or, in the case of the Pampas fox native to South America, the genus Lycalopex.

"In general, in mammals, species reproduce with their own species," explains Kays. "Sometimes, if they have not been separated for such a long evolutionary period, it can happen that different species reproduce. We occasionally see this with coyotes and wolves, but it usually happens when one of the animals is very common in a region and the other is very rare".

Pampas foxes are not rare, but are widespread throughout their range in South America. How has this unprecedented hybridization occurred and what implications does it have for the possible fox-dogs of the future?

(Related: The challenge of saving the rarest wolf in the world)

Dogxim died in March of this year and the cause of his death is unknown. In general, animal hybrids of this type can present genetic anomalies that endanger their survival.

How a fox met a dog
According to Kretschmer, it is likely that environmental disturbances contributed to the creation of Dogxim. The grassy plains of southern Brazil where Fampas foxes live are suffering from widespread habitat loss and development. Much of it is being converted to cattle pasture and human residences. Although pampas fox po[CENSORED]tions have remained stable, their habitat increasingly overlaps with that of domestic dogs, giving both more opportunities to mate.

Another factor, according to Bruna Szunwelski, co-author of Kretschmer's study, could be abandoned dogs.

"The practice of abandoning dogs is a crime in Brazil, but it still happens frequently," she says. "Pets and hunting dogs are often abandoned in natural areas by their owners, contributing to the increased presence of dogs in natural habitats, including protected areas."

Although a hybrid between species is usually an anomaly, with little chance of reproducing and giving rise to a new po[CENSORED]tion, it is increasingly difficult to predict how species may evolve as they are forced to adapt more quickly to the effects of climate change. and other environmental disturbances.

"The data suggest that hybridization has been much more common during the evolution of plants and animals than previously suspected, even among deeply divergent lineages," says Reiseberg.

Kay, however, thinks it unlikely that we will see more dog-foxes, partly because only one example has been found in all the years that dogs and foxes have lived in proximity, and because it is genetically risky.

"There are more likely to be genes that don't work together" in a completely new creature like Dogxim, she says, than in a species that has evolved over millions of years through gradual mutations that have proven advantageous to its survival.

Creatures created through hybridization often have health problems or other characteristics that make them less likely to survive. Dogxim's black fur, for example, contrasts with the typically paler tones of a Pampas fox, which are better camouflaged in the grasslands of its habitat.

Although he was reported to be healthy when he was transferred to the Mantenedouro São Braz state animal center in November 2021, Dogxim died in March 2023. The cause of his death is still unknown. Kretchmer and others did not learn of his death until August, when they called to request photos before the publication of their study.

According to a statement from SEMA, Brazil's Ministry of Environment and Infrastructure, the animal's death is being investigated by the State.

(Related: Was hybridization with Homo sapiens that caused the extinction of the Neanderthals?)

Dogxim's legacy
Regardless of whether Dogxim's existence was coincidental, its discovery raises important questions.

"Hybridization between species with different evolutionary trajectories can be a serious threat to the conservation of wild fauna," explain Kretcschmer and other authors in their study.

Although pampas foxes are not currently threatened in their native range, that could change. And hybrids like Dogxim could impact the native fox po[CENSORED]tion, potentially introducing new diseases and genetic weaknesses, hampering their prospects for survival.

The complexities and mysteries surrounding the discovery of Dogxim deserve further exploration, Kretschmer and his colleagues note in their article: studying the "consequences of hybridization on the genetics, ecology and behavior of wild po[CENSORED]tions will be essential to improve the conservation of this species." species".

https://www.nationalgeographic.es/animales/2023/09/primer-hibrido-perro-zorro-rareza-genetica-unica-doxim-brasil