Evolution of Snake Fangs - Article

[janeothejungle]

Another interesting article, blogging on peer-review work. Again, it's a little tech but pretty interesting stuff....

http://scienceblogs.com/pharyngula/2...fangs.php#more


Cheers,
Kat

[littleindiangirl]

Very interesting. A few rough patches with vocab, but very cool to read. The comments are great too. (up to a point... then its battle royal)

[Jenn]

Thanks for sharing that Kat. Very interesting and informative. And I just love how Mr. Myers throws around terms like "this is sweet" and "now hold on" in such a technical piece. And the comments just cracked me up!

Thanks again, I needed a good laugh.

[LadyOhh]

The comments are great too. (up to a point... then its battle royal)

That was a tough read for sure

Loved it!

[nwheat]

What an interesting article! The comment section has grown since I read it earlier this morning! Loved all the bonus info & refs from Dr. Fry!

[ncbloods]

Very interesting article.
You keep bringing the win with these scientific pieces.

[frankykeno]

Thanks Kat! I'm building a file of all sorts of interesting scientific papers and so forth on different aspects of snake anatomy so this is a welcome addition.

[Mendel's Balls]

Another interesting article, blogging on peer-review work. Again, it's a little tech but pretty interesting stuff....

http://scienceblogs.com/pharyngula/2...fangs.php#more


Cheers,
Kat

Again thanks for posting the link. It's so nice to have another person or two on here reading scienceblogs and pharyngula. It is very easy to miss very interesting things on there.

[Mendel's Balls]

Thanks Kat! I'm building a file of all sorts of interesting scientific papers and so forth on different aspects of snake anatomy so this is a welcome addition.

The paper discussed by PZ Meyers is based on Dr Fry's work. He has a website and forum (http://www.venomdoc.com/forums/). Eventually I think Fry will post a PDF copy of the actual paper that PZ blogged on under "publications". So hopefully you'll be able to add that one to your file soon as well. (http://www.venomdoc.com).

[Mendel's Balls]

The lead author of the paper...Freek Vonk discusses his work on the July 31st Nature podcast. You can listen to it here. It is at ~24:24 of the half-hour show.


I pasted a transcript from the show below. Adam Rutherford is one of the hosts of Nature Podcast.

Adam Rutherford: Now it's generally a good rule to do your best to avoid snakebites. For Freek Vonk from the University of Leiden in the Netherlands, it's not an option. He is the lead author on a paper in this week's issue, in which he gets his teeth into the evolutionary origin of venomous fangs. I spoke to Freek and asked him about the different types of fangs that snake species brandish. Nature 454, 630–633 (31 July 2008)

Freek J. Vonk: Well, a few group of front-fanged snakes including the cobras and the vipers which are the most famous ones and they have their fangs in front of their jaw, so more or less like the position of our canine teeth and then other than that we also have a large group of snakes which have rear fangs dentition, which means that the fangs are located more or less at the position of our wisdom teeth and one of biggest questions in evolutionary biology was, are those fangs evolutionary related or not.

Adam Rutherford: You've resolved that question. Explain to us what you have done and what sonic hedgehog has got to do with snake fangs.

Freek J. Vonk: Yeah the sonic hedgehog first of all is a gene that is highly expressed and involved in the formation of dentition. So what we did was to solve this question, we turned to the embryonic development and we looked at the expression of the sonic hedgehog gene and first of all what we found was that within the front fanged snakes, so where the fang ends up in the front of the upper jaw in the adult animal and the fang actually develops from the rear part of the upper jaw and then it is displaced forward by rapid growth of the upper jaw of one part relative to the other.

Adam Rutherford: So you have shown that in fact these teeth once the fangs at the front and the fangs at the back are actually derived from the same evolutionary precursor. (my emphasis)

Freek J. Vonk: Exactly, so what we also showed was that the rear fanged snakes there the fangs develop from its own developmental tissue. So if you compare it with our own dentition, each quadrant of our upper and lower jaw develops from one tooth forming tissue. So in the rear-fanged snakes it is as if our wisdom teeth would develop from their own tooth-forming tissue and other than that we showed remarkable similarity in developments between these rear-fanged tissue and the front-fanged snakes and if we map that over the evolutionary tree, we see that the most parsimonious explanation would be that those fangs are all derived from a rear fanged ancestor.

Adam Rutherford: And how does the association with fangs and venom, how is that evolved over the years?

Freek J. Vonk: Well first of all venom glands are older than the snakes themselves that is what we showed two years ago in Nature as well, the venom glands are about 200 million years old. They evolved in the lizard ancestors of modern snakes. But they were still quite small at that time, small and primitive what we call incipient venom glands. As soon as the advanced snakes evolved, the venom glands in the lower jaw, because they had both got lost and they modified, evolved the venom glands in the upper jaw to a very large and sophisticated venom gland in association with the teeth.

Adam Rutherford: Okay, so now snakes are not your run-of-the mill model organism, I have worked on fruit-flies and mice in my time. How do you actually go about performing this type of experiments on snakes?

Freek J. Vonk: Well first of all the fact that snakes are not a model organism is actually a good thing for me, because we can consider snakes as a sort of experiment form by evolution, because all the model organisms like mice, chickens, and of course fruit flies, they have been investigated extensively, but snakes has a totally different morphology with elongated bodies, fangs, venom glands, etc., so studying these animals can give us a broader knowledge of what evolution can do.

Adam Rutherford: Okay now I have had a quick look at your web site and you don't appear to be in the slightest bit afraid of snakes, whatsoever, where do you get your specimens from?

Freek J. Vonk: Well first of all I have a lot of friends also in Netherlands who keep snakes and they are very happy to provide me with eggs and I bred some snakes myself as well.

Adam Rutherford: And what about getting snakes from the wild?

Freek J. Vonk: Well you know I've been thinking about it, but if I have to be decide whether I want to get my eggs from captive specimens or from wild specimens I definitely choose for the captive specimens. I was in Indonesia at the beginning of this year and I caught a king cobra there which is the longest venomous snake in the world. And we found this king cobra we also found her nest and well about 20 eggs in there and no way would I ever have been able to take only one egg with me, because it was just too beautiful to see in the wild.

Adam Rutherford: So you prefer working with snakes in the lab or in the wild?

Freek J. Vonk: That's a very, very difficult question for me. I think I have to say both. I want to work in the lab because of course that's where most discoveries are made but I also absolutely love being in the field to find the snakes in their natural habitat, both of the things are just what I would like to keep on doing for the upcoming few years.

Adam Rutherford: And Freek have you ever been bitten?

Freek J. Vonk: I've been bitten a lot of times, but always by non-venomous snakes and I try to keep it that way. I have had some very, very close encounters with venomous snakes, but I usually try to be very careful because a bite by a venomous snake, it is not very good.

Adam Rutherford: Well quite. Freek Vonk boldly going where, Indiana Jones fails to tread. You can see some rather cool pictures of Freek wrestling with some pretty scary looking snakes at his website that's http://www.slangengif.nl. Slangen is the Dutch for snake, just in case if you're wondering.