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DNA Analysis of Ancient Fossils Has Scientists Rewriting the Elephant Family Tree

PALAEOLOXODON ANTIQUUS HAS BEEN EXTINCT FOR 120 000 YEARS. BY APOTEA (OWN WORK) [CC BY-SA 3.0

A stunning example of how ancient DNA evidence and analysis impacts our understanding of evolutionary biology involves African elephants. New research published in 2017 confirms that the straight-tusked elephant (Palaeoloxodon antiquus) a species of giant elephants that roamed the earth 1.5 million to 100,000 years ago, is more closely related to today's African forest elephant than to its nearest living relative, the African savanna elephant.  

The study was a joint effort between teams at the University of Illinois at Urbana Champaign, led by Dr. Alfred Roca, and The Max Planck Institute for Evolutionary Anthropology, led by Dr. Matthias Meyer. Their findings add major evidence to the understanding that today's African elephants are two separate species and not one. 

Background on Paleogenetics

Paleogenetics is the study of the past through the examination of preserved genetic material from the remains of ancient organisms. The term was first introduced in 1963, as it related to the reconstruction of past polypeptide sequences. The first sequence of an ancient DNA , isolated from a museum specimen of the extinct quagga, was published two decades later, in 1984 by a team led by Allan Wilson. 

Paleogeneticists aren't interested in creating new organisms. Their focus is providing a scientific understanding of ancient DNA sequences because this genetic code is  the only direct witnesses of extinct species and of evolutionary events.  An excellent overview of this research is available at the UCSC Paleogenomics Lab, a project of Beth Shapiro, and Richard (Ed) Green

The new science allows researchers to study not only fossils collected in permafrost, but to recover very old DNA sequences from warmer places, where it degrades at a much faster rate.

A study by Meyer et al reconfigures the elephant family tree, placing the straight-tusked elephant (Palaeoloxodon antiquus) closer to the African forest elephant (Loxodonta cyclotis), than to the Asian elephant (Elephas maximus), which was once thought to be its closest living relative. Image credit: Asier Larramendi Eskorza / Julie McMahon.

Rewriting Elephant Family Tree

In the case of elephants, paleogeneticists analyzed DNA sequences to determine how straight-tusked elephants are related to three living elephant species -- the Asian elephant, the African forest elephant, and the African savanna elephant -- and the extinct mammoth.  

The mitochondrial analysis concluded that a shared ancestor of Palaeoloxodon antiquus and the African forest elephant lived sometime between 1.5 million and 3.5 million years ago.

Their closest shared ancestor with the African savanna elephant lived between 3.9 and 7 million years ago.

Nuclear DNA told the same story.

“From the study of bone morphology, people thought Palaeoloxodon antiquus was closer to the Asian elephant. But from the molecular data, we found they are much closer to the African forest elephant,” said co-author Dr. Yasuko Ishida, from the University of Illinois at Urbana-Champaign.

Palaeoloxodon antiquus is a sister to the African forest elephant; it is not a sister to the Asian elephant or the African savanna elephant,” Dr. Roca said.

GlamTribal and Anne of Carversville friends want to understand the true origins of the earth's species and elements used in their own GlamTribal Woolly Rising mammoth bone jewelry.

Understanding evolution is a complex topic -- especially when humans are using scientific tools that are very young, and we are not scientists. 

 


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