A genetic research on elephants proposes a new family tree

The new possible elephant family tree (Image courtesy Asier Larramendi Eskorza / Julie McMahon)
The new possible elephant family tree (Image courtesy Asier Larramendi Eskorza / Julie McMahon)

An article published in the journal “eLife” describes a genetic analysis on elephants based on genetic analysis of the three existing species and the straight-tusked elephant (Palaeoloxodon antiquus), which is extinct but sampling of DNA from its bones was accomplished. A team of researchers led by Matthias Meyer of the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, proposes a new family tree for elephants different from the one currently used.

The straight-tusked elephant is a species of big elephant that lived between 780,000 and 50,000 years ago in Europe and the Middle East. The long-standing idea among paleontologists is that the straight-tusked elephant was the closest relative of the Asian elephant (Elephas maximus). This new research tried to test it using genetic analyzes based on the latest advances that made it possible to extract DNA from straight-tusked elephants’ bones found in two sites in Germany.

Matthias Meyer is a veteran of research in the field of paleogenetics, the discipline that generally studies the DNA of ancient humans but in this case directed a research that goes beyond hominids. For the first time, researchers at the Max Planck Institute for Evolutionary Anthropology have been able to extract DNA from very old bones, 120,000 and 244,000 years, found in a temperate climate.

Other researchers such as Alfred Roca of the University of Illinois at Urbana-Champaign also collaborated in the sequencing. The result was the complete sequencing of the mitochondrial DNA and the partial nuclear DNA of the two fossils of the straight-tusked elephants.

The mitochondrial DNA analyzes indicate that a common ancestor of straight-tusked elephant found and the African savanna elephant (Loxodonta africana) lived between 1.5 and 3.5 million years ago. The oldest common ancestor with the African forest elephant (Loxodonta cyclotis) lived between 3.9 and 7 million years ago. The analysis of the nuclear DNA provided results consistent with that of mitochondrial DNA.

The relationships of the straight-tusked elephant with its present’s cousins were deduced by studying the bones morphology of the various species but the genetic analyzes show a different story. The researchers found that the straight-tusked elephant is a sister species of the African forest elephant. The relationships with the Asian elephant and the African savanna elephant is more distant.

This research also adds further evidence that African savanna elephant and African forest elephant are two distinct species. For a long time the latter one was considered a subspecies of the first one and this is not just a classification problem interesting for scientists only.

Elephants in Africa are now in danger because of poaching, so the strategies to save them must take into account the fact that there are two separate species. For example, they need to avoid mixing specimens of the two species in an attempt to repopulate a certain area.

Paleogenetics, but also paleogenomics that apply modern technologies to extinct species, has already helped to better understand the history of hominids and therefore of humans, now results are also arriving for other mammalian families. In the case of elephants, this could contribute to their salvation, a further stimulus to carry out other research of this kind.

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