After sequencing the genome of African pachyderms, scientists from Harvard Medical School (USA), the University of Illinois (USA), and the University of York (UK) have shown thatthe African savanna elephant and the smaller one in the forest are not the same speciesInstead, they have been differentiated from each other for millions of years. To reach these conclusions, researchers have for the first time compared the Asian elephant, the African forest elephant, the African savanna elephant, the extinct woolly mammoth and the extinct American mastodon together.PLoS Biology.
“In terms of experimentation, we have faced a significant challenge inextract DNA sequences from two fossils (mammoths and mastodons) and align them with DNA from modern elephantsacross hundreds of sections of the genome, “says Nadin Rohland, lead author and researcher in the Department of Genetics at Harvard Medical School (USA). The researchers counted on the DNA of a single elephant of each species. However, they collected enough data from each genome to collect millions of years of evolution up to the point when the two elephant species first separated. The results show that the divergence of the two species occurred at a time close to the divergence of the Asian elephant and woolly mammoths.“The separation between the African savanna elephant and the African forest elephant is almost as old as the separation between humans and chimpanzees”explains Michi Hofreiter, a researcher at the Department of Biology at the University of York (USA), specializing in the study of ancient DNA.
The savanna elephant has an average height from the cross of about 3.5 meters while the average height of the forest elephant is 2.5 meters. The savanna elephant weighs between six and seven tons, almost twice that of the forest elephant. DNA analysis has revealed a wide range of genetic diversity in each of the species. The savanna elephant and woolly mammoth have very low genetic diversity, Asian elephants have medium diversity, and forest elephants very high diversity. Researchers think this is due to thevariation in levels of reproductive competition between males.
? Now we have to treat forest elephants and savanna elephants as two different animals for conservation purposes, because since 1950, all African elephants have been conserved as one species ,? says Alfred Roca, Associate Professor in the Department of Science Animals from the University of Illinois (USA) “As forest elephants and savanna are two very different animals, the forest elephant should become a higher priority when it comes to conservation,” he adds.
