TWS2021: Zoos provide healthy gene pool for painted dogs

African painted dogs are among the world’s most endangered species. Credit: Cassandra Miller Butterworth

African painted dogs are among the world’s most endangered species. These predators are widespread, albeit insignificantly, in various pockets of the continent in the wild. The largest contiguous ecosystem in which they roam extends across Botswana and neighboring countries. Other, much smaller groups are found as far afield as Libya, Algeria, Senegal and Ethiopia.

Because they require very large hunting ranges, the main threat to painted dogs is human activity, particularly from habitat destruction and conflicts with farmers. As a result, the International Union for Conservation of Nature considers African dogs to be colored (Lycaon drawing), also known as the endangered African wild dog.

Zoos around the world keep captive groups of painted dogs, and given the state of the animals at risk in the wild, some zoos may one day need to provide dogs for rehoming projects. Because of this, it is increasingly important to get an accurate sense of the genetic flow of painted dogs at the various zoos that keep dogs in Europe, South Africa, Australia and North America, according to TWS member Cassandra Miller Butterworth, associate professor of biology. at Penn State Beaver State University.

Captive populations of drawn dogs may serve as reservoirs to support small groups in the wild in future reintroductions. Credit: Cassandra Miller Butterworth

The origin of painted dogs in captivity is recorded in the so-called horse books, similar to the type used by horse breeders. These books record the origin of each individual so that captive breeders can better focus on healthy genetic diversity when pairing between individuals. But some of this information may not be entirely accurate – especially in cases where many individuals have been imported from the wild and the lineage is not known. Miller Butterworth and her colleagues wanted to supplement the information in the genealogical book with genetic analyzes.

Focus on zoos in the United States and Canada in recent research presented in The Wildlife Society’s 2021 Virtual Annual Conference, they analyzed 109 tissue samples from animals at 34 zoos and institutions collected for several years through 2018 – about 80% of the captive population in North America. These included 61 men and 48 females.

Miller Butterworth led a study published in genes which revealed that captive dogs in North America have fairly healthy genetic diversity, although not quite as diverse as captive groups in Europe.

“The good news is that we found that the population has not yet reproduced,” she said. “Overall, they have maintained good genetic diversity – more than the wild populations sampled.”

The analysis provided some uncertainty in the pedigree of some dogs as well and fixed two errors in the genealogy book. In all, Miller Butterworth and colleagues assigned paternity to 10 unknown cases and fixed three errors where the parent was incorrectly registered.

The researchers also estimated effective clan size – the number of dogs that contribute to the next generation by breeding. Because painted dogs live in high hierarchical enclosures, many dogs do not breed, sometimes making it difficult for biologists who want to introduce the genes of a particular animal, for example.

“The social hierarchy is in flux, even if it is [zoo staff] “I remove a dog temporarily for a medical procedure for it, and another dog can take its place in the hierarchy,” Miller Butterworth said.

But the data her team collected could at least help biologists take action to help maintain or improve diversity, such as sterilizing over-represented individuals or over-represented alpha males in a gene pool.

Captive painted dogs of North America had a fairly high genetic diversity. Credit: Cassandra Miller Butterworth

The ultimate goal of these analyzes, she said, is to harmonize genetic information about captive painted dogs with zoos on other continents in an effort to maintain high diversity. In this way, captive populations can be managed globally rather than region by region, or even zoo by zoo.

Better information about these populations can also help wildlife managers make decisions about which animals not to mix with, despite the great diversity. Since some groups of drawn dogs have been isolated for so long, it is likely that they have evolved specific genetic adaptations to their environment. In some cases, for example, wildlife managers may not want to mix painted dogs of East African ancestry with those of southern ancestry. In other cases, the genetic diversity of a small population may be very limited, and for long-term preservation there is no choice but to introduce genes from drawn dogs whose ancestors came from far away.

Miller Butterworth said these questions are difficult to answer, and will have to be asked on a case-by-case basis. But she hopes her research can at least provide key data that managers can use to make those tough decisions.

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