Cosma has to go and show off with a magisterial demonstration of why he is the smartest man on the internet: he’s written an exceptionally thorough description of heritability and IQ. It’s not a light read (statistics and genetics!), but it’s probably the most informative thing I’ve read in a month or more.
I’m sure I’m going to have to read it a few more times before I’ve absorbed it all.
One concept that is sometimes used in developmental biology is the idea of the “master control gene” or “master switch” — a single gene whose expression is both necessary and sufficient to trigger activation of many other genes in a coordinated fashion, leading to the development of a specific tissue or organ. It’s a handy concept on which to hang a discussion of transcription factors, but it may actually be of rather limited utility in the real world of molecular genetics: there don’t seem to be a lot of examples of master control genes out there! Pax-6 is the obvious one, a gene that initiates development of the eye, and other genes may be mentioned in certain stem cell pathways, but even in the eyes of vertebrates, for example, eye development is more complicated than a single switch, and similarly, many other developmental processes seem to use multiple or redundant regulatory controls — the cases where we have a single gene bottleneck are either rare or poorly represented in the literature.
They’re still at least pedagogically useful, though — it’s a simple case of imposition of a specific developmental pathway on a patch of tissue.
Hmmm. Estimates of the cost of the war in Iraq range from $4.4 to 7.1 billion per month. If I assume about $5 billion, it looks like we’re throwing away about $7 million per hour in that effort; so it looks like a little bit more than a half-hours worth of bloody war costs us $4 million. So let’s just stop for about 40 minutes, OK?
What was the point of that calculation? The government is threatening to shut down the Arecibo Observatory unless they can cough up $4 million dollars for its operating budget for the next three years. Wow.
The National Science Foundation, which has long funded the dish, has told the Cornell University-operated facility that it will have to close if it cannot find outside sources for half of its already reduced $8 million budget in the next three years — an ultimatum that has sent ripples of despair through the scientific community.
Shall we trade three years of science for less than an hour’s worth of war? That sounds like a no-brainer to me. The observatory doesn’t even kill anybody in normal operation. Or is that considered a strike against it?
Take a look at the winners of The 49th International Conference on Electron, Ion and Photon Beam Technology and Nanofabrication Bizarre/Beautiful Micrograph Contest. It’s itty-bitty art and weirdness!
Feathers only rarely fossilize, so the distribution of feathers in dinosaurs is difficult to determine. Sometimes feathers mark the bones, though, and bones do preserve well. Here’s an example: the forearm of a Velociraptor retains an array of small bony bumps evenly spaced along its length. What could they be?
I got some email today with lots of constructive suggestions (See? Not all my email is evil!) for how we ought to change the education of biology students — such as by giving them a foundation in the history and philosophy of our science, using creationist arguments as bad examples so the students can see the errors for themselves, etc. — and it was absolutely brilliant, even the parts where he disagreed with some things I’d written before. Best email ever!
Of course, what helped is that I spent my summer “vacation” putting together a new freshman first semester course for biology majors that I’m teaching for the first time right now, and it’s exactly the course he described. It was eerie, like one of my future students had invented a time machine and come back into the past to tell me what to do. A lot of the course content is locked up behind a password-protected firewall, I’m afraid, but just to show you what I’m talking about, I’ll put the course schedule below the fold.
The vertebrate jaw is a product of evolution — we have a serially repeated array of pharyngeal structures as embryos (and fish retain them in all their bony glory as gill arches), and the anterior most arch is modified during our development to form the jaws. The fact that they’re serially repeated raises an interesting possibility: what if, instead of just the one developing into a jaw, others were transformed as well? You could have a whole series of jaws!
One animal has done exactly that. The moray eel has modified one of the more posterior pharyngeal arches into a second pair of jaws, with a set of muscles that can slide it forward to bite prey already held in the mouth.
When we look at the face of another person, we can recognize specific features that have familial resemblances. In my family, for instance, I can recognize a “Myers nose” that my grandmother and my father and some of my siblings and kids have, and it’s different than my wife’s or my mother’s nose. These are subtle differences in shape—a bit of a curve, a knob, a seam—and their inheritance suggests that these differences are specified somehow in the DNA. If you think about it, though…how can whether the profile of a nose is straight or curved be encoded in a linear stretch of nucleotides? The complicated answer is that it isn’t—morphology is a consequence of epigenetic interactions during development—but we know that the alleles present in the genome do contribute in some significant way to three-dimensional form. How?
We don’t know all the details. This is one of those huge research problems that has gaping holes, full of promise and interest, where we don’t understand exactly how all the pieces fit together. However, here’s an important point that is relevant to other, larger issues in evolution: even where we lack full information about mechanisms, we can roughly perceive the shape of the answer, and that helps us rule out many alternative explanations and guides us in the general direction of a more complete understanding.
People’s noses are a difficult subject for research; we don’t get to define human crosses, people tend to be a little snippy about telling them who to breed with and taking their genes apart, and humans are awfully slow to breed. Fish are better experimental animals, much more pliable and faster and more prolific in their breeding. Some fish, such as the African cichlids, also have highly diverse populations and species with easily recognized and often quite dramatic morphological differences—and we can explore how those differences are generated by genetic and molecular differences in development. In particular, we can start to figure out how fish jaws are shaped by developmental processes.
Once we’ve defeated the creationists (hah!), we’re going to have to manage the next problem: well-meaning but ill-informed animal rights activists. Nick describes a recent article that tries to claim we can reduce animal use in labs — and it even has a couple of respectable scientists signing on to that nonsense.
And it really is nonsense. We don’t understand everything that is going on inside animals, and to figure it out, we actually need to look inside them. There’s no other way. If you want to examine patterns of gene expression inside the developing mouse brain, you have to extract their brains (needless to say, a lethal process) and examine them with a host of tools. Isolated cells in a petri dish aren’t the same thing. To simulate something with a computer, you need to know the parameters of what you’re simulating.
Using our imaginations and inventing what we think might be going on rather easily leads to absurd results … and the way I recognized that they were absurd is that I’ve actually looked at the processes involved.
Look into this one, everyone: the Coalition on the Public Understanding of Science (COPUS), another attempt to coordinate efforts to improve public outreach and science education. They have some worthy goals:
- Building the COPUS network – Underpinning the COPUS effort is a growing network of organizations and individuals who share a common goal: engaging sectors of the public in science and increasing their appreciation and understanding of the scientific enterprise. Find out more about participating in the COPUS Network.
- Developing state-level benchmark science-indicator reports on the importance of science to the U.S. economy and standard-of-living
- Supporting a national effort to promote the public understanding of science in a year-long celebration: Year of Science 2009 (also available: Year of Science 2009 fact sheet [PDF])
- Integrating efforts with the Understanding Science website project currently under development at the University of California, Berkeley
If you’re involved with any kind of scientific outreach organization, register with them — they’ve got a long list of science groups. I particularly like the fact that they’re herding together a grassroots effort to celebrate a Year of Science in 2009, the Darwin bicentennial year, since there doesn’t seem to be any national leadership on the issue otherwise.
