South America has more canid species than any place on Earth, and a new UCLA-led genomic analysis shows that all these doglike animals evolved from a single species that entered the region just 3.5 million to 4 million years ago. The scientists had assumed that the diverse species came from multiple ancestors.
Is it even more shocking? The tallest and shortest plants are related.
The rapid emergence of extreme variations in the height, size and diet of South American canids can be traced back to some of the key genetic mutations that have been introduced artificially.
The research, which was published in the Proceedings of the National Academy of Sciences, shows how quickly new carnivore species can evolve and spread in environments without competition.
There are ten species of dog and wolf in South America. The fox, bush dog and maned wolf are more unusual than the other seven.
Scientists had a theory about how South America became home to so many different types of canid. 3 million years ago, the volcanic strip of land known as the Isthmus of Panama allowed the free movement of animals between continents. Scientists assumed that multiple canid species had entered through the isthmus at different times, giving rise to existing and now- extinct species.
Daniel Chavez is a researcher at Arizona State University and Robert Wayne is a professor at UCLA. They studied the locations, quantity and types of genetic changes among the species.
According to the genetic data, there was a single ancestral canid population that arrived between 3.5 million and 3.8 million years ago. The researchers said that the ancestors must have made their way south through the newly developed Panama corridor and then just a narrow strip of savannah.
Chavez said that all of the canid species came from a single invasion. When populations can interbreed easily, there were a lot of canid species, but they weren't very genetically distinct.
The thin strip of land west of the Andes is where these species spread all over South America. Between 1 million and 3 million years ago, the 10 species that are present today emerged.
The maned wolf, the tallest and most long-legged canid in South America, and the shortest bush dog are related to wolves and African wild dogs. The height difference is caused by changes in the genes that regulate leg length.
Chavez said there were other hypercarnivores related to the bush dog. "Maybe they were bigger in size, so to compete, the ancestors of the bush dog got smaller, and eventually stopped competing for meat."
The rapid speciation of domestic dogs is similar to the rapid speciation of humans.
"South American canids are the domestic dogs of the wild animal kingdom in that they vary hugely in leg length and diet, and these changes happened very fast," Wayne said. We've done similar things to dogs. South America was empty of this type of animal. There was a lot of prey and no big or medium-sized animals to compete with. Nature allowed fast radiation in this area.
The relationships between the species and identified genes have been illuminated by the findings.
Wayne said thatDarwin's fox is a good example of the need for preservation. The most vulnerable species has very low levels of variation and genes that can be dangerous. Small populations can be saved through captive breeding programs.
More information: Daniel E. Chavez et al, Comparative genomics uncovers the evolutionary history, demography, and molecular adaptations of South American canids, Proceedings of the National Academy of Sciences (2022). DOI: 10.1073/pnas.2205986119 Journal information: Proceedings of the National Academy of Sciences
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