Nav: Home

Genetic study shakes up the elephant family tree

June 06, 2017

CHAMPAIGN, Ill. -- New research reveals that a species of giant elephant that lived 1.5 million to 100,000 years ago - ranging across Eurasia before it went extinct - is more closely related to today's African forest elephant than the forest elephant is to its nearest living relative, the African savanna elephant.

The study challenges a long-held assumption among paleontologists that the extinct giant, Palaeoloxodon antiquus, was most closely related to the Asian elephant. The findings, reported in the journal eLife, also add to the evidence that today's African elephants belong to two distinct species, not one, as was once assumed.

P. antiquus males stood up to four meters tall and weighed as much as 13 tons, more than twice the weight of today's largest elephants.

Understanding their genetic heritage is key to keeping today's elephants from going extinct, said University of Illinois animal sciences professor Alfred Roca, a co-author of the new study. Roca led research in the early 2000s that provided the first genetic evidence that African elephants belonged to two distinct species. Subsequent studies have confirmed this, as does the new research.

"We've had really good genetic evidence since the year 2001 that forest and savanna elephants in Africa are two different species, but it's been very difficult to convince conservation agencies that that's the case," Roca said. "With the new genetic evidence from Palaeoloxodon, it becomes almost impossible to argue that the elephants now living in Africa belong to a single species."

For the new analysis, scientists looked at two lines of evidence from African and Asian elephants, woolly mammoths and P. antiquus. They analyzed mitochondrial DNA, which is passed only from mothers to their offspring, and nuclear DNA, which is a blend of paternal and maternal genes.

The researchers relied on the most sensitive laboratory techniques to extract and amplify the DNA in P. antiquus bones from two sites in Germany - among the first DNA successfully collected from such ancient bones from a temperate climate.

"Up until now, genetic research on bones that are hundreds of thousands of years old has almost exclusively relied on fossils collected in permafrost," said Matthias Meyer, a researcher from the Max Planck Institute for Evolutionary Anthropology and first author of the paper. "It is encouraging to see that recent advances in laboratory methods are now enabling us to recover very old DNA sequences also from warmer places, where DNA degrades at a much faster rate."

The mitochondrial analysis revealed that a shared ancestor of P. 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.

The nuclear DNA told the same story, the researchers report.

"From the study of bone morphology, people thought Palaeoloxodon was closer to the Asian elephant. But from the molecular data, we found they are much closer to the African forest elephant," said research scientist Yasuko Ishida, who led the mitochondrial sequencing of modern elephants with Roca.

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

"Paleogenomics has already revolutionized our view of human evolution, and now the same is happening for other mammalian groups," said study co-author Michael Hofreiter from the University of Potsdam, an expert on evolutionary genomics. "I am sure elephants are only the first step and in the future, we will see surprises with regard to the evolution of other species as well."Michael

Understanding the genetic heritage of elephants is vital to protecting the living remnant populations in Africa and beyond, Roca said.

"More than two-thirds of the remaining forest elephants in Africa have been killed over the last 15 years or so," Roca said. "Forest elephants are among the most endangered elephant populations on the planet. Some conservation agencies don't recognize African forest elephants as a distinct species, and these animals' conservation needs have been neglected."
-end-
Leaders on the research team also included Eleftheria Palkopoulou and David Reich, of Harvard Medical School; and Beth Shapiro, of the University of California, Santa Cruz.

Numerous agencies and foundations supported this research, including the U.S. Fish and Wildlife Service.

Editor's notes:

To reach Alfred Roca, call 217-244-8853; email roca@illinois.edu.

To reach Matthias Meyer, email: mmeyer@eva.mpg.de.

To reach Michael Hofreiter, call 0049 331 9776321; email michael.hofreiter@uni-potsdam.de.

The paper "Palaeogenomes of Eurasian straight-tusked elephants challenge the current view of elephant evolution" is available online and from the U. of I. News Bureau.

University of Illinois at Urbana-Champaign

Related Dna Articles:

Penn State DNA ladders: Inexpensive molecular rulers for DNA research
New license-free tools will allow researchers to estimate the size of DNA fragments for a fraction of the cost of currently available methods.
It is easier for a DNA knot...
How can long DNA filaments, which have convoluted and highly knotted structure, manage to pass through the tiny pores of biological systems?
How do metals interact with DNA?
Since a couple of decades, metal-containing drugs have been successfully used to fight against certain types of cancer.
Electrons use DNA like a wire for signaling DNA replication
A Caltech-led study has shown that the electrical wire-like behavior of DNA is involved in the molecule's replication.
Switched-on DNA
DNA, the stuff of life, may very well also pack quite the jolt for engineers trying to advance the development of tiny, low-cost electronic devices.
Researchers are first to see DNA 'blink'
Northwestern University biomedical engineers have developed imaging technology that is the first to see DNA 'blink,' or fluoresce.
Finding our way around DNA
A Salk team developed a tool that maps functional areas of the genome to better understand disease.
A 'strand' of DNA as never before
In a carefully designed polymer, researchers at the Institute of Physical Chemistry of the Polish Academy of Sciences have imprinted a sequence of a single strand of DNA.
Doubling down on DNA
The African clawed frog X. laevis genome contains two full sets of chromosomes from two extinct ancestors.
'Poring over' DNA
Church's team at Harvard's Wyss Institute for Biologically Inspired Engineering and the Harvard Medical School developed a new electronic DNA sequencing platform based on biologically engineered nanopores that could help overcome present limitations.

Related Dna Reading:

Best Science Podcasts 2019

We have hand picked the best science podcasts for 2019. Sit back and enjoy new science podcasts updated daily from your favorite science news services and scientists.
Now Playing: TED Radio Hour

Climate Crisis
There's no greater threat to humanity than climate change. What can we do to stop the worst consequences? This hour, TED speakers explore how we can save our planet and whether we can do it in time. Guests include climate activist Greta Thunberg, chemical engineer Jennifer Wilcox, research scientist Sean Davis, food innovator Bruce Friedrich, and psychologist Per Espen Stoknes.
Now Playing: Science for the People

#527 Honey I CRISPR'd the Kids
This week we're coming to you from Awesome Con in Washington, D.C. There, host Bethany Brookshire led a panel of three amazing guests to talk about the promise and perils of CRISPR, and what happens now that CRISPR babies have (maybe?) been born. Featuring science writer Tina Saey, molecular biologist Anne Simon, and bioethicist Alan Regenberg. A Nobel Prize winner argues banning CRISPR babies won’t work Geneticists push for a 5-year global ban on gene-edited babies A CRISPR spin-off causes unintended typos in DNA News of the first gene-edited babies ignited a firestorm The researcher who created CRISPR twins defends...