S'moa DNA

Scientists from Down Under have extracted DNA from feathers of the extinct moa, the 2.5 meter tall birds that dominated New Zealand’s terrestrial ecosystems until the arrival of humans and non-native mammals about 700 years ago.

Previously, DNA had been extracted from the feathers of modern birds and from museum specimens of birds that have gone extinct in historical time, and only from the base or quill end of the feathers.

The moa study showed that viable DNA could be obtained from older, subfossil feathers and from the distal end of the feather, the rachis and barbs. Scientists are not seeking to use the DNA to clone the moa, but to identify the species of moa that they come from.

The success with moa feathers demonstrates that useful information can be obtained from subfossil feathers and from parts of feathers not previously considered useful in genetic analysis.

Reference: Nicolas J. Rawlence, Jamie R. Wood, Kyle N. Armstrong, and Alan Cooper, 2009, DNA content and distribution in ancient feathers and potential to reconstruct the plumage of extinct avian taxa. Proceedings of the Royal Society, B, October 7, 2009 276:3395-3402; published online before print July 1, 2009, doi:10.1098/rspb.2009.0755

Photo credit: Extinct Monsters by Rev. H. N. Hutchinson, illustrations by Joseph Smit (1836-1929) and others. 4th ed., 1896. Plate XXIII between pages 232 and 233.

DNA dream time

So how close are scientists to being able to clone a now-extinct species?

Ideally, scientists would start with a species that has recently gone extinct, and one for which we have tissue samples. Australia’s extinct Tasmanian tiger fits these criteria. The last-known captive animal died in 1936.

A team of scientists have inserted part of a bone-making gene from the Tasmanian tiger into a mouse embryo and found that it functioned properly. This marked the first time that DNA from an extinct species successfully induced a functional response in another living organism.

However, scientists are not making plans to exhibit a cloned Tasmanian tiger anytime soon. Through a gene-by-gene study scientists can hope to learn the functions of the genes from extinct species, but assembling an entire animal from fossil genetic material is still the realm of science fiction.

Reference: Pask, A. Behringer, R.R., and Renfree, M., 2008. Resurrection of DNA function In Vivo from an extinct genome. PloS One 3(5)

Photo credit: http://dsc.discovery.com/news/2008/05/20/gallery/tasmanian-tiger-540x380.jpg

DNA from Museum drawers

Scientists have recovered DNA from mammoth hair that had been stored in a drawer at room temperature for the 200 years since the 1799 discovery of a naturally mummified mammoth.

This discovery raises the prospect of sequencing DNA from the hair and feathers of other specimens from museum drawers.

We are still far from cloning extinct organisms from preserved DNA, and a Jurassic Park scenario is still science fiction, but these discoveries, while controversial, have established a new discipline, creating lab standards and research protocol for rigorous and repeatable results.

The information from fossil DNA helps to clarify the relationships between extinct animals and their living descendants.

Reference: Penn State University Webb Miller. Science, 317 (5846), 1927 (Sept. 28, 2007)

Photo credit: Stephan Schuster Lab, Penn State

Oldest DNA

Fossil DNA hunting is a recent phenomenon, as it was long assumed that the molecules could not survive the vagaries of time and preservation to become fossils.

The current claim for oldest preserved DNA comes from 419-million-year-old salt deposits from Canada. This is an amazing claim, as previous “oldest DNA” reports are from animals only tens of thousand years old.

Every claim of old DNA is subject to intense scrutiny and is accepted only after successful independent trials to replicate the results. The 419 million year old DNA is from salt-loving or halophilic bacteria, representatives of which are still around today and which provide a comparison for the fossil DNA sequences.

The discovery of halophiles gives encouragement to looking for microbes in other unusual places...like Mars. Click on today's title to learn more.

Reference: J.S. Park, et al.,, 2009, Geobiology 7 no. 5, p. 515-523, Haloarchaeal diversity in 23, 121 and 419 MYA salts

Ancient accidental pollinators

Back in the days before plants developed flowers to attract insects to help disperse their pollen, wind was the main agent of pollenation.

However, paleontologists recently argued that some pre-flowering plants had pollen receptors located deep within the plant so that wind-borne pollen would be unlikely to reach them. These scientists suggest that a little-known group of fossil insects called scorpionflies might have served in pollinating these pre-flowering plants.

These fossil scorpionflies (descendants of which are still around today) have narrow, elongate mouthparts suited for reaching far into plants and feeding on fluids, so it is unlikely they could have ingested the large pollen grains. Instead, pollen grains may have stuck to the insect’s head or mouthparts as they fed, and scorpionflies became accidental pollinators—the first known pollinators of pre-flowering plants.

Reference: Ren, D., Labandeira, C., Santiago-Blay, J., Rasnitsyn, A., Shih, C., Bashkuev, A., Logan, M., Hotton, C., & Dilcher, D. (2009). A Probable Pollination Mode Before Angiosperms: Eurasian, Long-Proboscid Scorpionflies Science, 326 (5954), 840-847 DOI: 10.1126/science.1178338)

Photo credit: http://z.about.com/d/animals/1/0/n/g/18149_web.jpg

Serendipity with a backhoe

This is a story of what happens when construction workers have some appreciation for interesting rocks and fossils they come across in the course of their daily tasks:

While excavating oil sands in a mine near the town of Ft. McMurray, Alberta, Canada, a heavy machinery operator uncovered the skeleton of a plesiosaur, the extinct, long-necked reptile that inhabited Mesozoic seas.

The skeleton had been fragmented by its excavation by backhoe rather than small hammers, chisels and brushes, but when pieced back together, it was judged to be 80% complete.

The find is significant because it is the earliest North American occurrence of a plesiosaur, extending the known geologic range of these animals to the early part of the Cretaceous Period and this find also expands the known geographic range of plesiosaurs in North America.

Reference: Journal of Paleontology November, 2009, Earliest North American occurrence of a plesiosaur

Photo credit: http://www.dinosaurjungle.com/focus_plesiosaur.jpg. For more on plesiosaurs, go to this site or click on today's title.

The first beetle

The oldest known fossil beetle has been discovered not in an outcrop, but in a museum drawer. A 296 million year old insect has been reclassified as a beetle, pushing back the origin of beetles by millions of years.

The evolutionary success of beetles is traditionally explained by their two-stage life style—they pass through ecologically distinct larval and adult stages that allow them to exploit different niches.

However, the new find creates a large gap between the first appearance of beetles and the diversification of beetles that occurred 65 million years later, and suggests that the innovation of the two-stage lifestyle was not the initial cause of beetle diversity.

This opens the door to other explanations for beetle success, such as the proliferation of the plant species that was favored by the beetle larvae.

Reference: Journal of Paleontology November, 2009, The Earliest Beetle identified (Olivier Bethoux)

Photo credit: This is a much younger fossil beetle from the Eocene (15 million-year-old) Florissant Fossil Beds of Colorado, which preserves a wide variety plant and animal life. Click on today's title for more information.