Wednesday, 27 October 2010

Can we bring the Dinosaurs back?

This weekend I spotted some Dinosaurs by the Blackpool lights. Unfortunately they're not real since the only living descendants of Dinosaurs today are Birds. But the worlds most famous Dino-hunter, Jack Horner, is helping the man who he thinks has the potential to change all this. His name is Hans Larsson. His work involves merging paleontology and molecular biology in order to understand major evolutionary changes. One of his goals it to 'switch on' dormant genes or change the regulation of currently active genes so that ancient traits, lost through evolution, will be expressed. Hans Larsson believes that although birds have lost many dinosaurian traits, it may be possible have them expressed once again.

So far, Larsson and his postdoctoral assistant have began working on chicken embryos. Traits such as a long tail have been lost in birds, and we can see the gradual reduction in tail length in the fossil record. Larsson found that although the tail grows very well in early development, "at a particular stage in development everything comes crashing to a halt". They found that retinoic acid, which stimulates the release of an protein called sonic hedgehog, “pushed tail growth to the upper range of normal development. It had some effect, but it didn’t break it out of the cycle.” This gave an Larsson an idea of how complex the growth of the tail is. Unfortunately there isn't much research on how to sustain growth in a tail, so Larsson and his assistant have had to do everything from scratch.

“The experiment I’m envisioning is that you have a single embryo developing in the egg with multiple injection sites and multiple kinds of molecules to be really fine-tuning the regulation of genes,” says Larsson. “We’ll be able to inject different parts of the embryo at different times of development with different things. If we do that, if the timing and position are correct, we should be able to manipulate lots of different kinds of morphologies—feathers, wings, teeth, tails.

“It would take just a little bit of time to work out each one of those systems in very great detail, which we’re now doing for the tail. Other people are doing it for the limbs for clinical work. And teeth are being worked out by other people for mammals and such, and then we can just sit down and play with all these in concert, which has never been done before.”

This'Chickenosaur' may resemble something from the coelurosaurs, a clade of theropod dinosaurs which resemble birds more than carnosaurs.“Birds are dinosaurs, so technically we're making a dinosaur out of a dinosaur. The only reason we're using chickens, instead of some other bird, is that the chicken genome has been mapped, and chickens have already been exhaustively studied. A number of people in a number of different places are moving forward with the project slowly and carefully,” says Horner.

Below is a video by Hans Larsson about the work he does.

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