The last known blue antelope was probably shot in South Africa over 200 years ago, the only large mammal on the continent to be extinct in modern times. Also called the bluebuck, the antelope was prized for its skin and hunted by European settlers. Yet many details of its time on the planet remain a mystery – only a handful of specimens are preserved in museums around the world.
A recent study in Molecular biology and evolution Now collects the creature’s genetic history and sheds light on its family tree and later years. Researchers reveal that the blue antelope population was already in a fragile state before the arrival of European settlers. But the study confirms that, as had long been suspected, the settlers were responsible for his disappearance.
“Our results suggest that this was already a small and probably fragmented population,” says co-author Elisabeth Hempel, a paleogeneticist at the Berlin Museum of Natural History and the University of Potsdam, Germany. “It is possible that the species is already on the slow path to extinction. But it was most likely the humans who pushed him overboard.
The study excited others in the field because the researchers were able to produce a complete genome sequence from ancient nuclear DNA extracted from a nearly 10,000-year-old blue antelope fossil tooth. The process was not easy. The researchers tried to use nuclear DNA from 25 fossils; only one gave enough for sequencing. And they may have been lucky – the fossil was found in a cave that had protected sensitive DNA from the worst of the heat and humidity.
“This is a proof of concept and a very important step,” says Mikkel Sinding, a former DNA researcher at the University of Copenhagen, Denmark. “It has been very difficult for geneticists to obtain old genomes from Africa. There’s really terrible preservation in most environments. Previous genetic analysis of the blue antelope had to settle for mitochondrial DNA, which is more abundant but tells an incomplete story.
In addition to the fossil sample, the study sequenced the complete genome of a surviving blue antelope specimen approximately 200 years old. This allowed the team to compare the two sequences and see how the species’ DNA has changed over some 10,000 years. They found that the genomic diversity of the blue antelope was much lower than in similar species, indicating a low population size.
“The genome showed that the population size of the blue antelope was already low at the end of the last ice age around 10,000 years ago,” Hempel said. This was likely due to the gradual replacement of its grassland habitat with scrub and forest, thus constricting the species into smaller habitats. “It is possible that the blue antelope survived for a long time with this low diversity until the arrival of European settlers and firearms,” she adds.
The genome also answered some outstanding questions about the animal’s evolutionary history. “There was an old discussion about whether the blue antelope was its own species or not,” Hempel says. Data from the study showed it to be its own species, in part by indicating that the two distinct blue antelope genome sequences were more closely related to each other than to any other species. He also showed that the blue antelope was more closely related to the extant sable than the roan antelope.
“This species was only known to Europeans for a very short time before it became extinct,” says Sinding. “So this article highlights that it was really something unique.”
There is still a lot to be said about the story of the blue antelope. Researchers are now looking to ask more targeted questions, including whether the animal migrated. To do this, they need to extract and sequence more nuclear DNA from more fossil samples from across the region. “This nuclear genome shows that more is worth testing,” says Hempel.
Also encouraged by the findings, other scientists will attempt the same with fossil remains of other species. “It’s really difficult, but now we know it’s possible to get genomes at that age; it sets the tone for future research projects,” says Mariana Ribeiro, a graduate student at the University of Porto, Portugal, who works on roe antelope genomics. “If you know it’s possible, then you try harder to do it.”
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