Load-bearing adaptation of women’s spines

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Those of you who have been pregnant, or have been a partner to someone who has been pregnant, are familiar with one among many common consequences: lower back pain. It’s not surprising—pregnant women are carrying this low-slung 7kg (15lb) weight, and the closest we males can come to the experience would be pressing a bowling ball to our bellybutton and hauling it around with us everywhere we go. This is the kind of load that can put someone seriously out of balance, and one way we compensate for a forward-projecting load is to increase the curvature of our spines (especially the lumbar spine, or lower back), and throw our shoulders back to move our center of mass (COM) back.

Here’s the interesting part: women have changed the shape of individual vertebrae to better enable maintenance of this increased curvature, called lordosis, and fossil australopithecines show a similar variation.

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Bisexual flies and the neurochemistry of behavior

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On the one hand, this is a strange tale of mutant, bisexual, necrophiliac flies, and you’ve got to love it for the titillating nature of the experiments. But on the other, much more interesting hand, it’s a story about drilling down deeply into the causes of a complex behavior, and tracing it to a single gene product — and it also reveals much about the way the chemicals sloshing about in the brain can modulate responses to stimuli. Work by Grosjean and others on a simple Drosophila mutant, genderblind, which causes flies to be indiscriminate about gender in their courtship, opens up a window into how sexual responses are shaped and specified.

Think about human sexual responses. Some of us, when we see an attractive woman, are at least mildly aroused; others are have their sexual interest picqued when they see an attractive man; still others might feel sexual urges when they see a shoe, or a plush animal, or a pot of baked beans. No matter what the stimulus, these are all biological responses, with something in the environment matching some trigger in our brains and initiating a cascade of neural, neurochemical, and hormonal activity that leads to sexual behaviors. The question we want to address is what every step in the biology is doing; unfortunately, human behaviors are both too complex and not amenable to ethical experimentation, so we turn instead to simpler organisms that allow us to find simpler causes and carry out thorough experiments to probe the behavior.

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Great glowing spiders

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I’ve known that scorpions have fluorescent cuticles — if you go out into the desert with a black light and shine it on the ground, the scorpions will often glow green and blue and be easy to spot. I had no idea that many spiders exhibit the same phenomenon, but there they are, glowing away. I may have to visit my local head shop (in Morris? Hah!) and get some black light bulbs to see what the fauna in my living room is up to.

Fluorescence is actually a fairly common property: all it requires is a molecule called a fluorophore that can absorb and capture transiently photons of a particular wavelength, or energy, and release them at a lower energy. What this means is that a fluorescent substance absorbs light at one range of wavelengths, and then re-emits those photons at a longer wavelength; there is a color shift. In the case of black light posters and spiders and scorpions, they are absorbing light at wavelengths our eyes can’t detect (wavelengths below about 400nm, or ultraviolet light) and shifting it to a wavelength we can see, for instance to a nice blue at 450nm, cyan at around 500nm, or green at about 550nm. So to test this, all you need is a dark room, a spider, and a light source that glows at the wavelength that is absorbed by the fluorophore, and a detector (like, say, your eyes) that can collect light at the emission wavelength.

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Let’s have a presidential science debate!

As Sheril hinted earlier, there is now a formal call for a science debate by the presidential candidates.

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A CALL FOR A PRESIDENTIAL DEBATE ON SCIENCE AND TECHNOLOGY

Given the many urgent scientific and technological challenges facing America and the rest of the world, the increasing need for accurate scientific information in political decision making, and the vital role scientific innovation plays in spurring economic growth and competitiveness, we, the undersigned, call for a public debate in which the U.S. presidential candidates share their views on the issues of The Environment, Medicine and Health, and Science and Technology Policy.

I’ve expressed my opinion of such an effort before — I think it’s an excellent idea, but suspect that most of the candidates would refuse to submit to it. Not only is there the science test factor, in which we’re asking them to get evaluated on something most know nothing about, but the Republican slate in particular is full of astonishing idiots who hold beliefs contradicted by science. I just can’t believe they’ll step up on the podium for this one, unless they perhaps see an opportunity to hijack the discussion to promote their personal piety.

I still want it to happen: this is an opportunity to apply pressure to our candidates to have some minimal, basic science literacy. As I previously mentioned, though, those airheads with nice hairdos that populate the television media are even more dim than the candidates themselves, and must not be allowed anywhere near the event — I want wildlife biologists armed with tranquilizer guns at the doors, with orders to shoot Russert and Blitzer and anyone from Fox News on sight. How about if we put Natalie Angier, Carl Zimmer, John Horgan, Ira Flatow, John Tierney, and Cornelia Dean on a panel asking questions? How about if we ask Science and Nature to send representatives with questions? I would dearly love to see a debate on any subject where the candidates had to deal with issues of some substance.

So let’s all make a noise about this one, OK? Rattle the cages, and tell the candidates we want to hear opinions on topics that matter for the leader of a technological, 21st century society, rather than the usual tripe.

Springtime in Oregon, when the evodevo is in bloom…

The University of Oregon and Indiana University have this wonderful Integrated Graduate Education and Research Traineeship in evo-devo that was, unfortunately, established long after I graduated from the UO. I have to say that it is a great idea, and it isn’t their fault I’m a superannuated anachronism. Anyway, the important thing is that they are hosting a symposium on evolution, development, and genomics: “From Patterns to Process:
Bridging Micro-and-Macroevolutionary Concepts through Evo-Devo” on
4-6 April, in beautiful Eugene, Oregon. And look at the speakers they have lined up!

Keynote Speakers

Scheduled Speakers

A springtime meeting in Oregon in which I get to hear the latest in evo-devo from some of its biggest names and a rather significant detractor (Coyne)? Well, that settles it for me — I’m going. This sounds like spectacular fun.

Fish Experiment

Over the past few days I have been running my trials for experiment that was oh so controversial last time I blogged about it. I have been placing two groups of six fish into two solutions containing 0.5% ethanol and 0.25% ethanol. I place them into the solutions for a few hours then compare grouping behaviors. I compare grouping using a computer program to take a picture of the group every minute for 30 minutes. I then use a different computer program to measure the area of the group. The fish spend approximately 10 hrs. in the ethanol solution. After that I put them in a tank with just water, the “sober tank,” overnight and start all over again in the morning.

I am hoping to observe the development of alcoholic tolerance over the course of this experiment. Other studies that I have found doing this sort of thing exposed the fish to alcohol 24/7. I am hoping to observe similar results, but limiting the exposure time to the alcohol. Whether this will happen or not I do not know. When I crunch all of the numbers next week for my report I will find out how this experiment turned out.

What does it take to turn a stem cell into a cure?

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Last week, I reported on this new breakthrough in stem cell research, in which scientists have discovered how to trigger the stem cell state in adult somatic cells, like skin cells, producing an induced stem cell, a pluripotent cell that can then be lead down the path to any of a multitude of useful tissue types. I tried to get across the message that this is not the end of embryonic stem cell (ESC) research: the work required ESCs to be developed, the technique being used is unsuitable for therapeutic stem cell work, and there’s a long, long road to follow before we actually have stem cell “cures” in hand. A review on LiveScience emphasized similar reservations. Seizing on this one result as an excuse to end research on ESCs would be a great mistake.

So let’s consider what it takes to turn a stem cell into a medically useful tool. One “simple” (we’ll quickly see that it is anything but) example is finding a cure for type 1 diabetes. We understand that problem very well: people with this disease have lost one specific cell type, the β cells of the pancreas, which manufacture insulin. That’s all we have to do: grow up a dish full of just one cell type, the β cells, and plant them back in the patient’s gut, and presto, no more diabetes (setting aside the chronic difficulty of removing whatever destroyed the patient’s original set of β cells, that is). Sounds easy. It’s not.

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