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March 11, 2010

Eggshell DNA

One of the problems with studying extinct species is that... well, they're extinct. With fossils, especially, it is difficult to learn much about a creature besides what its skeleton tells us. This is why the idea of extracting fossil DNA is so exciting. With strands of fairly intact DNA, scientists could analyze different genes in an extinct creature, giving some clue to things like coloration, evolutionary lineage, etc. If there was enough really well preserved DNA, it could even be possible to bring extinct species back to life.

Elephant Bird Skeleton and Egg
There's a major problem with extracting DNA from fossils, though. DNA is an extremely fragile molecule; it does not take long for it to degrade once a creature dies. Even the best preserved fossil bones have partial DNA at best. While this does prevent a lot of ethical questions, like whether we should bring extinct creatures back if we could, it makes understanding those creatures much more challenging.

A recent article published in the Royal Society journal offers a new possibility in recovering fossil DNA, however. Scientists looked, not to bones, but to eggshell to try and extract DNA. They successfully recovered genetic material from the eggshell of Aepyomis, the elephant bird of Madagascar, for the first time. They were also able to get DNA from New Zealand duck and moa eggshells, and Australian emu and owl eggshells, the oldest of which was 19,000 years old. Because eggshells are pretty resistant to decomposition, it makes sense that they would preserve the DNA better than bone.

This is an exciting step towards perhaps getting a fuller understanding of extinct species. It's still no where near dinosaurs, but it provides a new way to look. It will be interesting to see where this sort of research takes the studies of zoology and paleontology in the future.

Source: Discovery Channel- Fossilized Eggshells Yield DNA