Dance of Development
I enjoyed the fruit fly embryonic development video from this post so much, I decided to animate it. Grow, little alien … grow like the wind!!!
My short ode to development, inspired by the image above, (via biocanvas):
Epithelial cells line surfaces and cavities throughout the body, forming skin, glands, and tracts. This mouse embryo has been genetically engineered to allow for the visualization of epithelial cells, showing the pattern of whisker placement on the face.
Image by Evan Heller, Rockefeller University.
The dance of biological development tops our best ballet or even our most magnificent marches. And it is truly a dance, as this video of a developing fruit fly embryo makes beautifully clear:
Those cells, darting to and fro! They are pulled in and out of furrows, sensing the position and identity of their neighbors, migrating and multiplying at the whim of invisibly overlapping chemical gradients. It’s a journey in both space and time, the emergence of greater form from a horde of interconnected individuals.
The whisker patterns of the mouse above are just one of the many awe-inspiring end results of developmental organization. While only a few of those nodes will sprout whiskers, the larger pattern drawn by development can be seen radiating outward toward the tail like rays from the sun.
These relics of organization often remain invisible in adult animals, although sometimes they do show through (like when humans have “stripes”). Jason Silva has said that “to understand is to perceive patterns.” I offer this as an accompanying idea: To exist at all is to emerge from the sum of patterns.
Animal Eye Close-Ups
Jeepers creepers, where’d you get them peepers?
Aren’t eyes just great? It’s amazing to see how evolution has solved a single problem in such a myriad of ways. Actually, to be more accurate, it’s amazing to see that evolution has molded such diverse and intricate machinery from perhaps the same starting point.
That’s right. Although it’s long been thought that animal eyes evolved separately as many as 40 times, eyes most likely owe their varied existence all to one single gene. That gene is named Pax6, and it’s a master control switch for many of the things that end up becoming eyes in jellyfish, flies, snakes and even humans. It doesn’t make eyes on its own, but acts like the conductor during the symphony of development. The protein it makes looks like this:
Now that we are sequencing more and more genomes, and deciphering the precise DNA sequence of Pax6 in all of those diverse creatures, we are able to map out how that gene has changed over time. Like a game of molecular telephone, DNA sequences (usually) get more and more scrambled as they spread into new species. Follow the molecular breadcrumbs back far enough, and you can find out where you came from.
And for all those oodles of eyes, all gorgeous, intricate and exquisite, Pax6 might hold the key to seeing where vision began.
Enjoy this virtual microscope, and explore a zebrafish embryo down to the individual cell! All without leaving your computer or spending those pesky hours preparing it in a lab.
This species of fish, Danio rerio, is used in labs around the world to study development. Especially eye development, because … well. it has a huge eye.
Taken from the BBC series, “Inside the Human Body”, this CGI animation draws upon developing embryo scans to recreate the formation of an embryo’s head and facial features.
The result is unsettling, yet breathtaking.
Like puzzle pieces coming together, it’s the story of your philtrum. Now you can amaze your friends with this awesome knowledge. Also, this is a little creepy.
How can the union of two parental germ cells lead to such complex and varied adult bodies? Sperm meets egg, and a few billion or trillion cells later, you have all the parts of an adult. From humans to fruit flies, we all begin this way.
An intricate (even that word strikes me as painfully inadequate to describe this complexity) chorus of genes turning off and on create cascading waves of signaling molecules. Some molecules say this is top and this is bottom. Others say this is head and this is tail, and still others say that this part will fold and morph and migrate just so, one day becoming your spinal cord or your gut.
We study this developmental dance by watching the embryos of simple animals like fruit flies. What you’re watching above is a new imaging technique that allows every cell in an embryo to be tracked in three dimensions as the organism grows.
By taking images from different sides of the embryo and putting them into powerful computers (11 terabytes of information!), the whole path from egg to larva is drawn. More at the link below.
(via Nature News & Comment)
We know that some ancestral fish-like being one day got tired of breathing the same damned water everyone else was and slowly set foot on land. All land-dwelling animals descend from this early adventurer. But how did we make the switch from fins to legs?
Turns out that the genes that control fin development and limb development in fish and mice are interchangeable. A fish expressing a key gene involved in limb growth taken from a mouse still grows normal fish fins. ANd a mouse expressing a fishy gene? You guessed it, it grows cute little furry paws.
That means that even before that fish stepped out on the beach, the genes were there to carry us to any number of eventual ends: wings, legs, flippers or fins. Now that we know that so many of the switches that control limb growth are the same, researchers are going to work on what makes them different.
It also means that our dreams of mermaids are set back yet again.
(via Discover Magazine)
Just what causes puberty to start [early] is not fully understood, and the researchers plan to pool data collected for the study to try to determine if there are associations between puberty onset and factors such as diet or exposure to endocrine-disrupting chemicals.
Since 1997, the percentage of 7 year-old girls that are reaching puberty has, in some cases, doubled. This quote points at two possible causes - diet/obesity and environmental exposure to endocrine-disrupting chemicals (food, household, other).
It’s important to be concerned, and to direct energy at finding the cause. It is equally important not be alarmed, though, and not to blame everything (like water bottles, hamburgers or cleaning chemicals). Keep calm and science can lead us through this!
The image above shows fluorescently labeled grasshopper embryos. Three components of the embryo are labeled: The proteins nanos and hunchback, and the DNA in the many nuclei. The embryo images were then falsely colored and arranged into the floral design.
I'm Joe Hanson, Ph.D. biologist and host/writer of PBS Digital Studios' It's Okay To Be Smart. Check out my "Episode Extras" here. There's a lot of amazing science out there. Let's go discover it together.
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