Around 1800 came the end for the bluish shimmering antelope: Paleogenetic information now sheds light on the characteristics and history of the South African bluebuck. Researchers extracted and sequenced DNA from a museum specimen and a 9,950-year-old tooth. It is now the oldest paleogenome from the African continent. The analysis results make it clear that despite the small population size, the bluebuck was able to master the climatic changes of the last 10,000 years until the European settlers drove this species into extinction in the 17th century.
It is considered to be the first large mammal species in Africa to fall victim to humans in historical times: the bluebuck (Hippotragus leucophaeus) owes its name to a bluish-grey shimmering fur. Its range was a small area in southern Africa, where it appears to have coexisted with humans for at least 100,000 years. But in the course of European colonization in the region, it came under increasing pressure from the 17th century: the last bluebuck was finally shot around the year 1800 - only 34 years after its first scientific description.
Targeting the bluebok
A research team headed by Elisabeth from the University of Potsdam has dedicated itself to researching this species, which has remained somewhat mysterious. First, the scientists investigated the extent to which the specimens declared in museums as "Bluebuck" really belong to this species. It became clear that the species had only been documented very imprecisely before it became extinct: The researchers obtained mitochondrial DNA from ten museum pieces and were able to show through comparisons that only four are authentic. The others were specimens or body parts of other animal species.
In the current study, the scientists have now gone one step further: they have succeeded in obtaining two nuclear genomes from the bluebuck. One comes from a preserved specimen in the Swedish Museum of Natural History in Stockholm, while the second comes from a 9,300 to 9,800-year-old fossil tooth in the Iziko Museum of South Africa in Cape Town. As the team points out, the very ancient genome is something special: it is currently the oldest paleogenome of a living being from Africa. Far older ones are known from other parts of the world, but the high temperatures in Africa in particular limit the preservation of biomolecules, the researchers explain.
Information mirrored in DNA
As they report, the genetic analyzes of the paleogenome revealed that the bluebuck was related to the sable and roan antelopes. There is also a gene flow from the roan antelope to the bluebuck. Based on certain characteristics of the genome, it was now possible to draw conclusions about a previously unclear aspect: how numerous were the bluebucks once? It turned out that the genomic diversity of this species was much lower than that of the roan and sable antelope. "The genetic data reflect that the population size had been low since the end of the last Ice Age around 10,000 years ago - and thus also when the European colonists arrived in southern Africa in the 17th century," says Hempel.
According to her, this in turn means: “Despite their small range and population size, bluebucks have survived alongside humans in the region for the past 10,000 years. This changed when the European colonists reached southern Africa with guns,” says Hempel. It is thus clear that the Bluebuck was a species that fell victim to human impacts at the onset of the current biodiversity crisis.
Source: Museum of Natural History - Leibniz Institute for Evolutionary and Biodiversity Research, specialist article: Molecular Biology and Evolution, doi: 10.1093/molbev/msac241; Sci Rep, doi: 10.1038/s41598-020-80142-2