Very pretty, but fundamentally wrong

This exercise in false equivalence, Duelity, is beautifully animated but promotes a poor idea. It’s basically two videos, one telling the Christian creation myth inaccurately and in the style of a scientific explanation, and another that inaccurately summarizes the evolution story as if it were holy writ. There’s a pretense that these are equally valid descriptions of the history of the world that is completely wrong, and that amplifies the errors throughout the individual stories from mere irritations to dishonest propaganda.

The comments there are largely positive. All I can assume from that is that a lot of people are easily swayed by good production values.

I hope it’s not a metaphor for the current situation

I have to consider this a rather dispiriting story:

In 1818, a whale oil dealer refused to pay a fish-product fine on whale oil, because a whale isn’t a fish. The inspector insisted on the tax, and a spirited court and public battle played out.

It’s dispiriting because you’d think the weight of scientific evidence (and if you prefer it, the testimony of no less an authority than Aristotle) would have settled this case easily, but no…the whale lost and was declared a fish.

Circadian Clock Neurons

Here’s another interesting question from our most recent neurobiology exam. With some luck PZ won’t get irritated that I keep recycling my work. This paper was a bit of a brain thumper but also very interesting after deciphering what it’s talking about.

3) Summarize this paper and describe both the neural circuit and the genes underlying this particular rhythm.
Stoleru D, Peng Y, Agosta J, Rosbash M (2004). Coupled oscillators control morning
and evening locomotor behavior of Drosophila. Nature 431:862-868

The roughly one hundred bilaterally arranged circadian clock neurons in adult fly brains occur in six groups: dorsal neurons (DN1, DN2, DN3), dorsal lateral neurons (LNdS), and the PDF neuropeptide expressing small and large ventral lateral neurons (LNvS). Extirpation via proapoptotic genes was used to assess that D.melanogaster lacking LNvS in natural light/dark conditions displayed little change however in continuously dark environments yield arrhythmicity. Time intervals in the light/dark experiment were determined using Zeitgeber time in which lights on (sunrise) corresponds with ZT0 and lights off (sunset) corresponds with ZT12. Although the two LNvS cell groups have an imperative role in rhythmic gene expression, neurons expressing circadian photoreceptor cyrptochrome (cry) genes were also found to assist rhythmicity in natural light/dark conditions.

Green fluorescent protein reporter was used to stain the six clock neuron groups, determining that the cry-GAL4 driver, which facilitates cry gene expression, is present in all dorsal and ventral lateral neurons (LNdS and LNvS) and in two dorsal neurons (DN1). The proapoptotic gene hid was used to excise the cry gene in LNdS and LNvS generating cry-GAL4;UAS-hid flies that were arrhythmic in both natural light/dark and continuously dark environments. The dorsal neuron groups (DN1, DN2, DN3) are mostly unaffected by hid expression meaning that because cry-GAL4;UAS-hid flies are arrhythmic in both environments, these neuron groups are incapable of maintaining circadian rhythms independently.

Crossing D.melanogaster exhibiting the Pdf-GAL80 gene, which represses GAL4-mediated transcriptional activity, with flies exhibiting green fluorescent protein in circadian neuron groups via Pdf-GAL4 and cry-GAL4 drivers yielded flies without green fluorescent protein. This means that the cry and Pdf promotors, segments of DNA that control gene expression, coupled with GAL80 genes override and prevent their corresponding GAL4 drivers from transcribing. With the crossing of cry-GAL4 driver and Pdf-GAL80 repressor, and other mixed crosses, green fluorescent protein was observed only in some circadian neuron groups.

Crossing Pdf-GAL80 with cry-GAL4;UAS-hid allowed researchers to determine the effects of extirpating PDF+, CRY+PDF-, and CRY+ neurons on D.melonogaster circadian rhythm. They found that flies extirpated of CRY+ neurons were phenotypically arrhythmic and flies extirpated of PDF+ neurons had diminished morning lights-on anticipation with normal evening lights-off anticipation. Flies extirpated of CRY+PDF- had diminished evening lights-off anticipation and normal morning lights-on anticipation. These flies maintained a circadian rhythm in continuous darkness indistinguishable from wild type flies based unimodally on the morning oscillator. The phenotypes of these three strains of D.melonogaster are not affected by whether the environment is light and dark or continuously dark meaning that the oscillators are not driven by light. Using deductive logic, the researchers concluded that PDF+ neurons correspond to lights-on behavior and oscillate independently of CRY+PDF- neurons, which correspond to lights-off behavior.

Green fluorescent protein techniques for visualizing neurons confirm that the CRY+PDF- and PDF+ oscillators are coupled through PDF- axonal processes that protrude from the LNd neuron group into the LNv region. Immunostaining visualization techniques reveal that PDF neuropeptide travels in the opposite direction that the PDF- axons extend, that is, from the LNv to LNd neuron group. PDF neuropeptides function to coordinate the lights-on anticipation behaviors in the morning with the independently oscillating lights-off anticipation behaviors in the evening.

References:
Stoleru D, Peng Y, Agosta J, Rosbash M (2004). Coupled oscillators control morning
and evening locomotor behavior of Drosophila. Nature 431:862-868

Great glowing spiders

Blogging on Peer-Reviewed Research

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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Christmas shopping?

One of the small disadvantages of academia is that we get hopelessly busy just before Christmas, which makes squeezing in the gift shopping difficult. I’m probably not even going to step into a store until sometime around the end of next week. That’s why you have to appreciate these online gift suggestions. I’m leaning towards the Televangelists’ Rapture Early-Warning System as a universally useful gift for my family members of all faiths. Even the atheists should like the half-hour warning before the Rapture so they can rapidly convert!

Watching the creationist pots coming to a boil

All right, who’s in charge of pool predicting the location of the next big creationist trial? The odds on Florida have just gone up: another Board of Education member has said something stupid.

I would support teaching evolution, but with all its warts. I think that some of the facts have been questioned by evolutionists themselves. I would want them taught as theories. That’s important. They could be challenged by others and the kids could then be taught critical thinking and they can make their own choices.

Thank you, Linda Taylor. Warts: name two. Theory: define the term. Answer the following multiple choice question:

Who is best qualified to make informed choices about complex scientific theories?

  1. Scientists with years of training in the subject, and qualified science teachers who understand the fundamentals of the theory.
  2. Creationists who won’t even commit to an estimate of the age of the earth.
  3. Members of the board of education who have absolutely no training in the sciences.
  4. Children who are just being introduced to the topic for the first time, haven’t read any of the primary literature, and who are entirely dependent on the competence of the instructors who have given them an outline of the general story.

So I’m leaning towards a big blow-up in Florida. Now you might think Texas should be in the lead, what with the obvious clown circus in the Chris Comer story, but I suspect that the Texas creationists have grossly overreached and are going to face a serious backlash — Texas biology professors are pissed off and are mobilizing to fight back. Floridans are going for the slow and steady buildup.

Florida parents are also contributing to the problem. Let’s see more Florida parents rising up to protest so I can dial those odds down a notch.

People behaving badly

We shouldn’t leave the Moslems hanging with all the blame for bad behavior — so here’s some more deplorable activities that have show up in my mailbox in the last few hours.