Basics: Neurulation

When we had last seen our basic embryo, it had gone through gastrulation — a process in which cells of a two-layered sheet had moved inward, setting up the three germ layers (endoderm, mesoderm, and ectoderm) of the early embryo. In particular, cells at the organizer, a tissue that induces or organizes migrating cells, had rolled inwards to set up specific axial mesoderm structures: the prechordal plate, which will underlie cranial structures, and the notochord, which resides under the future hindbrain and spinal cord. At this point, the embryo has an outer layer of ectoderm, and lying under part of it, a band of prechordal mesoderm and notochord. In addition, the ectoderm is loaded with a molecule called BMP-4, a member of the TGF-β family of signaling molecules, and under its influence will go on to make skin, not nervous system. So what next?

[Read more…]

How to move a big rock

Sometimes we’re a little bit mean to engineers here — there’s the Salem hypothesis, for instance, that notes that creationist apologists who claim to be scientists often turn out to be engineers. In compensation, though, watch this video of a Michigan man with simple, clever strategies for moving massive objects. I was impressed. I guess the ancients didn’t need the assistance of high-tech alien astronauts to build impressive stone structures, all they needed was a Wally Wallington.

Super cool moon rocks!!

Is there anyone in the Stevens County area who reads this blog? Just in case, I’ll mention this event sponsored by the UMM Geology Club to anyone interested in coming on down.

Geology Club will be displaying lunar rocks and soil samples collected during
the Apollo missions to the moon this Thursday night at 7:00 p.m. in Sci.
1650. These rocks are brought to us by Geology Professor Jamey Jones, which
he currently has on loan from NASA. This event is open to the public, so
come and check it out!

What: Super cool moon rocks!!
Date: Thursday, March 22
Time: 7:00 p.m.
Place: Sci. 1650 (the Physical Geology lab)

For some cool information about the lunar rocks, check out this link:
http://cda.morris.umn.edu/%7Ejonesjv/petrology/moonrocks.html

Curing malaria by helping mosquitos

Here’s a clever (I think) observation in the efforts to eradicate malaria: the mosquitos that transmit malaria are also infected with the disease-causing parasite, so maybe if we cure malaria in mosquitos, it will end one intermediate step in the transmission chain. It sounds like a crazy idea, but recent experiments suggest that it might just work. It’s got the advantage of allowing the use of transgenic techniques on the mosquito population, where you don’t have to worry about patient’s rights or whether a few of your experimental subjects will die during the procedure, and you can just let the untreated population wither away and die, and no one can complain. There are a few other ethical concerns, however.

[Read more…]

Interconnections everywhere

You really should take a closer look at this map of publication links between scientific disciplines. Here’s the description:

i-508bc95dbd69cfbdf67e978d97580982-science_links.jpg

This map was constructed by sorting roughly 800,000 published papers into 776 different scientific paradigms (shown as pale circular nodes) based on how often the papers were cited together by authors of other papers. Links (curved black lines) were made between the paradigms that shared papers, then treated as rubber bands, holding similar paradigms nearer one another when a physical simulation forced every paradigm to repel every other; thus the layout derives directly from the data. Larger paradigms have more papers; node proximity and darker links indicate how many papers are shared between two paradigms. Flowing labels list common words unique to each paradigm, large labels general areas of scientific inquiry.

There’s an amazingly detailed version of the map available at Seed, and it visualizes an important point: all of the sciences are interconnected, sometimes very indirectly, but the contacts are there. When some clueless ideologue (like Michael Egnor, who is up to the same old tricks again) tries to split off a major subset and pretend it is irrelevant, he has to ignore the breadth of science.

Evolution of the jaw

i-ccbc028bf567ec6e49f3b515a2c4c149-old_pharyngula.gif

What do you know…just last week, I posted an article dismissing a creationist’s misconceptions about pharyngeal organization and development, in which he asks about the evidence for similarities between agnathan and gnathostome jaws, and what comes along but a new paper on the molecular evidence for the origin of the jaw, which describes gene expression in the lamprey pharynx. How timely! And as a plus, it contains several very clear summary diagrams to show how all the bits and pieces and molecules relate to one another.

The short summary is that there is a suite of genes (the Hox and Dlx genes, which define a cartesian coordinate system for the branchial arch elements, Fgf8/Dlx1 genes that establish proximal jaw elements, and Bmp4/Msx1 genes that demarcate more distal elements) that are found in both lampreys and vertebrates in similar patterns and roles, and that vertebrate upper and lower jaws are homologous to the upper and lower “lips” of the lamprey oral supporting apparatus.

[Read more…]