Frogs re-evolved lost lower teeth

[n2doc]

Frogs re-evolved "lost" bottom teeth after more than 200 million years, according to new research.

Tree-dwelling Gastrotheca guentheri are the only frogs with teeth on both their upper and lower jaw.

The reappearance of these lower teeth after such a long time fuels debate about whether complex traits are lost in evolution or if they can resurface.

Scientists suggest this new evidence identifies a "loophole" in previous theories.

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http://news.bbc.co.uk/earth/hi/earth_news/newsid_9365000/9365076.stm

[Ian David]

1. ...

[RC]

5. A visit to the dentist must be a hoot.

[The Velveteen Ocelot]

2. The fact that there are frogs with teeth is disturbing anyhow.

[phantom power]

3. I thought modern evo-devo had already established that these traits can reappear...

fairly easily. Most of these changes happen by "disabling" of developmental pathways. The pathways themselves remain, but an upstream switch mutates. The pathway can be reenabled by future mutations.

:shrug:

[tularetom]

4. I think you meant to say god decided to create some frogs with teeth

Only pointy headed scientists believe that anything evolves.

[formercia]

6. Nothing new

There have been Dentists in Canuckistan for Generations.

[dimbear]

7. Evolution primarily occurs by turning genetic code on or off, not deleting it.

Everyone reading this has a perfectly good set of genetic instructions for a coat of fur and a tail, but in most cases those genes are turned off.

It's similar to deleting your porn. It first goes into a state where it's recoverable, and only goes away for good if you overwrite it.

This is the main explanation for so called parallel evolution, i.e., why the placental mammals and marsupial mammals evolved such similar forms. They are turning on or off available sets of genes.