Alligator Genetics and the Development of Bird "Thumbs"

Here is a new article from open-access journal PLoS One: "The Evolution of HoxD-11 Expression in the Bird Wing: Insights from Alligator mississippiensis," (link) which uses color illustrations to explain the genetics and development of the finger digits in birds and alligators. Read the summary on Palaeoblog for a good explanation on the study. Basically, it's a study on Hox genes and how although developmentally birds seem to have digits 2, 3, and 4 from the ancestral 5, this is a result of a "hometic frameshift," causing HoxD-11 expression to move, so ancestrally, their digits are 1, 2, and 3, which is consistent with the fossil evidence such as Archaeopteryx as well as genetic evidence seen in their closest living relatives, the crocodilians.

It's satisfying when evidence adds up in such a neat way.

Anyway, on to the drawings!

Figure 1: Three levels to the avian digit homology problem: embryology, gene expression, and morphology
First of all, the illustrations in this article are just fantastic. Full of information, but designed in a clear way that is in no way overwhelming. There is a didactic use of color, which allows the viewer to follow each of the 5 digits across both development and evolution. The next example includes a more complex clade as well as specific fossil and extant examples.

Figure 2: The evolution of digit morphology
This drawing makes it so easy to compare across the cladogram. You can watch as the digits disappear one by one. I have seen similar illustrations used to show the gradual loss of toes in the evolution of the horse. Janel? You out there? This illustration on Wikipedia is awful! I know there are better ones out there.

And here are the more technical illustrations...

Figure 3: Identification of the alligator HoxD-11 exon 1 sequence.
Figure 4:The expression of HoxD-11 in alligator and chicken limbs.
I have to admit I often I roll my eyes at the use of photos in lieu of illustrations, but in this case they work amazingly well in tandem. Development is shown in similar stages in alligators and birds, both limbs, and you can trace the development to see where they diverge, and where and which fingers are lost in the bird.

How long could YOU survive?

I could survive for 54 seconds
===EDIT===

For more information about Velociraptors and Velociraptor safety, please visit the American Society for Velociraptor Attack Prevention at www.velociraptors.info. Know the enemy! Stay safe, people!

Evolution Tattoos

This was linked on Skepchick this morning: The Science Tattoo Emporium. Check out the 18 pages of amazing science-themed body art. Here are some of the evolution ones.

"Origin of an Epidemic" illustrates the owner's graduate research on the evolutionary history of the HIV virus. This is definitely my favorite of the bunch.

Darwin's finches, based on Darwin's first published drawings.

"Five Kingdoms" is a cladogram depicting the five major groupings of living organisms: Monera, Protista, Plantae, Fungi, and Animalia. The sea dragon is especially beautiful.

The very first phylogenetic tree, from Darwin's notebook.

And another Tree of Life, based on the drawing by Ernst Haeckel.

Evolution Time!

Found on Pharyngula (originally from MyConfinedSpace).
I would so buy this watch. Although, for it to be accurate, if our evolution from single cell to human was to be compressed to 12 hours, we'd still be fish at 11:00!

Dromaeosaur tails...

Were the tails of dromaeosaur dinosaurs (raptors) completely stiff or did they exhibit some amount of an S-curve? This is the question posed in a post last week on the blog Tetrapod Zoology (see sidebar), "What the hell is going on with dromaeosaur tails?" This new evidence has major implications for paleoartists!

Tsaagan mangas

It looks strange to me, but just because you're used to seeing something one way doesn't mean it's correct!

Why don't art and science mix? (this time, anyway)

Hey cool, someone agrees with me! Jonathan Jones of the Guardian posted this article, "Why don't art and science mix?" yesterday about the Darwin's Canopy art competition I blogged about last June. His thoughts on the various entries were the same as mine, if not expressed much more strongly:

"The Darwin's Canopy commission was a chance for artists to engage with science. What a shame they turned their backs on this challenge... This commission was a great chance for artists to engage with the most important idea of the last two centuries, to find ways of illustrating - and championing - the theory of evolution at a time when irrational religious forces menace Darwin's common sense revolution. What a chance for art to show it can engage with science, and also wade into a fierce debate! The artists have run a mile from any such challenge. Few address evolution at all."

So very true! I also agreed that of all the entries, the NHM thankfully picked one of the non-abstract proposals. Jones says:

"The proposal chosen, by Kovats, is a respectful homage to Darwin's own drawing of the tree of evolution. But the exhibition is a dismal insight into the total lack of interest in science displayed by most contemporary British artists."

Of course, going back to the title of his article, I would have to say that art and science do mix, quite easily! But in this case, yes, most of the artists dropped the ball. They should have commissioned some scientific illustrators instead of 'fine artists,' perhaps.

and my Coldplay obsession reaches epic levels...

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