« Home | Flu and asymptomatic infections » | Of dragons and microbes » | Grand rounds 2.09 » | Other topics » | 40 million infected with AIDS; but, some good news... » | U of Iowa faculty petition against ID released » | New malaria vaccine shows promise » | The ethics of avian flu response » | Video time capsule » | Tangled bank #41 » 

Friday, November 25, 2005 

Followup to "dragons and microbes" post

I discussed here new research on venom evolution that topples some old conventional wisdom. It seems this and another study are already making large waves in that field.

Genealogy of Scaly Reptiles Rewritten by New Research
The most comprehensive analysis ever performed of the genetic relationships among all the major groups of snakes, lizards, and other scaly reptiles has resulted in a radical reorganization of the family tree of these animals, requiring new names for many of the tree's new branches. The research, reported in the current issue of the journal C. R. Biologies, was performed by two biologists working at Penn State University: S. Blair Hedges, professor of biology, and Nicolas Vidal, a postdoctoral fellow in Hedges' research group at the time of the research who now is a curator at the National Museum in Paris.

Vidal and Hedges collected and analyzed the largest genetic data set ever assembled for the scaly reptiles known as squamates. The resulting family tree has revealed a number of surprising relationships. For example, "The overwhelming molecular-genetic evidence shows that the primitive-looking iguanian lizards are close relatives of two of the most advanced lineages, the snakes on the one hand and the monitor lizards and their relatives on the other," Vidal says.

"We gave this group the new name, 'Toxicofera' because of another discovery, reported in a related paper, that some lizard species thought to be harmless actually produce toxic venom, as do some snakes--including some large monitor lizards in the same family as the giant Komodo Dragon and some large species of iguanians." Vidal, Hedges, and other researchers report this and other discoveries about the early evolution of the venom system in lizards and snakes in a paper led by Bryan G. Fry, of the University of Melbourne in Australia, published in the current issue of the journal Nature. "It's a really startling thing that so many supposedly harmless lizards actually are venomous," Vidal comments, "but their sharing of this characteristic makes sense now that our genetic studies have shown how closely they are related."

This is a great example of how science works. Important new findings have come to light, and the rest of the evidence is re-examined in that light, to see what stays and what thinking may need to be revised. No one expects it to happen overnight, and a call is put out for others to investigate and test the new conclusions:

"Because the current tree has been widely accepted for nearly a century, I think there is going to be a delay of maybe a few years before the general scientific community gets used to the new tree," Vidal says. "If other research groups working in this area find the same pattern with additional genes, then I believe the scientific community may accept these results more quickly."

Note how there are no politics involved, no pressure to teach these new results. The investigators are confident enough in their own data that they can wait for other scientists to examine it, express skepticism, test it themselves, and add their own conclusions to the scientific literature. It may take several years, but if the data stand up and are repeated by others, the way students are taught *will* change--not because anyone was lobbied to do so, but because the evidence is strong and it would be folly not to acknowledge that. I look forward to following this in the coming years.

|

About me

  • I'm Tara C. Smith
  • From Iowa, United States
  • I'm a mom and a scientist, your basic stressed-out, wanna-have-it-all-and-do-it-all Gen Xer. Recently transplanted from Ohio to Iowa, I've spent most of my life in the midwest (with 4 years of college spent out east in "soda" territory). My main interest, and the subject of my research, is infectious disease: how does the microbe cause illness? What makes one strain nasty, and another "avirulent?" Are the latter really not causing any disease, or could some of those be possible for the development of chronic disease years down the road? Additionally, I've spent a lot of time discussing the value of teaching evolution, and educating others about "intelligent design" and other forms of creationism. My interest in history of science and medicine is also useful as a way to tie all of the above interests together. [Disclaimer: the views here are solely my own, and do not represent my employer, my spouse, that guy who's always sitting by the fountain when I come into work, or anyone else with whom I may be remotely affiliated.]
My profile

Links

Powered by Blogger
and Blogger Templates

Powered by Blogger

Creative Commons License
The Tangled Bank Locations of visitors to this page
Enter your email address below to subscribe to Aetiology!


powered by Bloglet


The Evolution Education Site Ring

This site ring is owned by John Stear

Previous Site

List Sites

Random Site

Join Ring

Next Site