Back to the future: Mastodon extends the time limit on DNA sequencing

Jul 24, 2007

In a new paper in the open access journal PLoS Biology, Michael Hofreiter from the Max Planck Institute for Evolutionary Anthropology in Germany, and colleagues from Switzerland and the United States, announce the sequencing of the complete mitochondrial genome of the mastodon (Mammut americanum), a recently extinct relative of the living elephants that diverged about 26 million years ago.

The sequence was obtained from a tooth dated to 50,000–130,000 years ago, increasing the specimen age for which such palaeogenomic analyses have been done by almost a complete glacial cycle.

The mastodon becomes only the third extinct taxon for which the complete mitochondrial genome is known, joining the superficially similar looking woolly mammoth, and several species of Moa, the giant flightless Australasian bird.

Using the mitochondrial genome sequence, together with sequences from two African elephants, two Asian elephants, and two woolly mammoths (obtained from previous work), it was shown that mammoths are more closely related to Asian than to African elephants. This shows the power of genetic data to clarify interrelationships, even in the case of well studied taxa.

Moreover, the researchers used the mastodon data as a calibration point, lying outside the Elephantidae radiation (elephants and mammoths), which enabled them to estimate accurately the time of divergence of African elephants from Asian elephants and mammoths (about 7.6 million years ago) and the time of divergence between mammoths and Asian elephants (about 6.7 million years ago).

These dates are strikingly similar to the divergence time for humans, chimpanzees, and gorillas, and raise the possibility that the speciation of mammoths and elephants and of humans and African great apes had a comm on cause. Despite the similarity in divergence times, the substitution rate within primates is more than twice as high as in proboscideans, showing that the molecular clock ticks differently for different taxa.

Citation: Rohland N, Malaspinas AS, Pollack JL, Slatkin M, Matheus P, et al. (2007) Proboscidean mitogenomics: Chronology and mode of elephant evolution using mastodon as outgroup. PLoS Biol 5(8): e207. doi:10.1371/journal.pbio.0050207.

Source: Public Library of Science

Explore further: The inside story: MRI imaging shows how plants can inspire new engineering materials

Related Stories

Rewriting the history of the Boaz mastodon

May 27, 2015

Through a combination of modern-day scientific sleuthing, historical detective work, and a plethora of persistence, researchers at the University of Wisconsin-Madison have rewritten the story of a celebrated ...

Recommended for you

Can pollution help trees fight infection?

4 hours ago

Trees that can tolerate soil pollution are also better at defending themselves against pests and pathogens. "It looks like the very act of tolerating chemical pollution may give trees an advantage from biological ...

Improving rice flour to aid food poverty

4 hours ago

A new, high-quality rice flour could help towards aiding global food poverty. "This rice flour serves not only as an alternative to wheat flour for those with wheat intolerance, but could also help to overcome ...

Stink bugs have strong taste for ripe fruit

6 hours ago

The brown marmorated stink bug has a bad reputation. And for good reason: every summer, this pest attacks crops and invades homes, causing both sizable economic losses and a messy, smelly nuisance—especially ...

Researchers discover how petunias know when to smell good

8 hours ago

Good timing is a matter of skill. You would certainly dress up for an afternoon business meeting, but not an evening session of binge-watching Netflix. If you were just a few hours off in your wardrobe timing, ...

User comments : 0

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.