It’s this:  airline passengers can’t use the bathroom an hour before landing.

It makes no sense. If somebody wanted to blow up an airplane, why would they have to do it during that period?  After all, they can go to the bathroom and prepare their devices two hours before landing, and the damage will be just as great.  The only reason I can see for this ludicrous regulation is a post facto reactivity to the last bomber: he went to the bathroom 20 minutes before landing.

Over at Slate, Christopher Hitchens discusses the latest moronic airline regulations — and the futility of thinking that we can prevent all terrorist bombings:

What nobody in authority thinks us grown-up enough to be told is this: We had better get used to being the civilians who are under a relentless and planned assault from the pledged supporters of a wicked theocratic ideology. These people will kill themselves to attack hotels, weddings, buses, subways, cinemas, and trains. They consider Jews, Christians, Hindus, women, homosexuals, and dissident Muslims (to give only the main instances) to be divinely mandated slaughter victims. Our civil aviation is only the most psychologically frightening symbol of a plethora of potential targets. The future murderers will generally not be from refugee camps or slums (though they are being indoctrinated every day in our prisons); they will frequently be from educated backgrounds, and they will often not be from overseas at all. They are already in our suburbs and even in our military. We can expect to take casualties. The battle will go on for the rest of our lives. Those who plan our destruction know what they want, and they are prepared to kill and die for it. Those who don’t get the point prefer to whine about “endless war,” accidentally speaking the truth about something of which the attempted Christmas bombing over Michigan was only a foretaste. While we fumble with bureaucracy and euphemism, they are flying high.

Oh, and here’s another Hitchens piece from the latest Vanity Fair: a frightening description of the pollution of the American military by Christianity.

There are lots of parasites in this world, but I know of only two cases in which the parasite actually evolved from its host. Both of these are cancers. One is the canine transmissible venereal tumor (CTVT), and the other a transmissible cancer affecting the Tasmanian devil.  A paper in this week’s Science (see also this report at the BBC) traces the origin of this cancer to a mutant cell in the nervous system.  More interesting — at least for our purposes — are the evolutionary implications.

The Tasmanian devil (Sacrophilis harrisii; see photo below) is the largest marsupial carnivore, with a range limited to Tasmania.  In 1996, researchers noticed that some devils were afflicted with “devil tumor facial disease”(DTFD).  This is a nasty disease (see photo below), with facial and throat metastases that usually kill the animal.  And DTFD is transmitted by biting, so tumor cells must be in the saliva or gums. (This leads me to suspect that the tumor has actually evolved to make itself more transmissible, since tumors that spread less easily would die off with their carrier.)

Murchison et al. looked at the DNA of 25 infected devils (both the individuals and their tumors) and of 10 “control” uninfected individuals.  The results were intriguing. First, all of the 14 genes examined showed that all the tumors had a similar genotype — a genotype palpably different from (and less diverse than) the devil hosts themselves. DFTD is a clone, which means it had a single origin, almost certainly a mutant cell in a single unlucky devil.

What kind of cell was it? The authors answered that question by looking at the “transcriptome,” the set of RNA molecules produced by DNA, which gives you an idea which genes are actually expressed.  The transcriptome of individual devils differed from that of the tumors, with the tumors showing much higher expression of those genes involved in the “myelinization pathway”: genes that build the myelin sheaths of nerves and fight off agents that attack nerves.

From this observation, the researchers conclude that the parasitic tumor originated from Schwann cells, a particular group of cell in the peripheral nevous systems that act as a neuron “tenders,” wrapping themselves around nerve axons to maintain myelin sheaths and helping those axons grow.

The differential expression of the tumor cells, and the identification of where they came from, gives scientists a marker for identifying the disease, and holds promise for eradicating it.  I have my doubts, though, for research is slow and the disease is spreading so rapidly that it could drive the devils to extinction within 25 years.

The evolutionary twist is that the tumor is now an independent parasite, derived from devil cells but no longer part of the devil body itself.  It can be thought of as a separate organism, genetically free to undergo independent evolution.  And its evolutionary interests are in conflict with that of the host from whence it came.  (The authors don’t dwell on this aspect of the problem.)

It’s not clear where that evolution will go, though. It’s possible that because transmission depends on virulence, or at least on the parasite’s ability to quickly get into the mouth,  the tumor could become more and more virulent, speeding up the extinction of not only the Tasmanian devil, but of the tumor itself.  (Here’s an example where evolution has no foresight!)

Increased virulence is not a certainty, though, for those tumors that kill the devils too quickly won’t get a chance to spread.   DFTD is like a cold: its spread requires its carrier to be active, and so extreme lethality is a detriment.  It may eventually evolve to become less lethal, but that may be too late, for evolution is slow and the tumor is already virulent enough to exterminate itself and its host.

One devil, named Cedric, appears to be naturally immune to the cancer, so perhaps some captive breeding may be in order.

Fig. 1.  A Tasmanian devil

Fig. 2.  A devil afflicted with DFTD

h/t: Greg Mayer

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Murchison, E. P. et al. 2010. The Tasmanian Devil transcriptome reveals Schwann cell origins of a clonally transmissible cancer.  Science 327:84-87.

Although Caturday is sacrosanct, even I admit that there are some things more important than kittehs.  For 2010 I wish all of us whirled peas.

The new Irish blasphemy law takes effect today, and here’s what it says:

A person who publishes or utters blasphemous matter shall be guilty of an offence and shall be liable upon conviction on indictment to a fine not exceeding €100,000.

“Blasphemous matter” is defined as matter “that is grossly abusive or insulting in relation to matters held sacred by any religion, thereby causing outrage among a substantial number of the adherents of that religion; and he or she intends, by the publication of the matter concerned, to cause such outrage.”

Where a person is convicted of an offence under this section, the court may issue a warrant authorising the Garda Síochána to enter, if necessary using reasonable force, a premises.

Of course, it’s still legal to insult somebody else’s political beliefs, or any other beliefs — just so long as you keep your mitts off religion.  I wonder if it’s blasphemy to insult someone’s faith in astrology, scientology, or healing with crystals.

a. The Irish should be ashamed of themselves for passing a law that makes a huge and influential sphere of human thought immune from criticism.

b. People should start testing this law immediately, though the 100,000-Euro law will be a disincentive.

The Chicago Tribune asked seven Republican and two Democratic candidates the following question:

Do you accept the theory of evolution? Please explain.

This question is of course guaranteed to send shivers down the spine of any candidate. They don’t want to look stupid and deny the established fact of evolution, but they also need to pander to their benighted religious constituents. So the question produces more waffles than IHOP. This would be funny if it weren’t so scary.

Their answers, and the take of one Illinois evolutionary biologist:

First the Republicans:

— Adam Andrzejewski: “Yes. As a practicing Catholic, I believe that God created Darwin. Let others debate the details.”

A complete cop-out, trying to gain a smidgen of credibility by mentioning Darwin but avoiding the whole issue.

— Bill Brady: “I accept the theory of creation, as I was taught, and believe the world has continued to evolve since.”

Another stupid cop-out.  He abnegates any responsibility for thinking simply because he “was taught” something. And the “theory of creation” says nothing about subsequent evolution. Did humans evolve after the first “creation,” or were they part of it?

— Kirk Dillard: “Science seems to support evolution but there is no doubt that I have seen the hand of God at work in my travels and everyday life.”

A bit better, but uses the weasel-word “seems” and quickly rushes to assure people that he’s seen God. What does God have to do with the question?

— Andy McKenna: “Yes, but I also believe that the process of evolution has been guided by the creative power of God.”

Well, at least a “yes,” though he’s buying theistic evolution.  It would be nice to know exactly how he thinks God guided evolution.

— Dan Proft: “The current political class in Springfield make me question the veracity of natural selection. That aside, I do not believe there needs to be a divide between religious belief and the scientific method. … The evidence seems to me fairly clear that, as Pope John Paul II wrote, human beings have a ‘common ancestry of life’ from which we have evolved.”

You can see, from the tendency of these candidates to drag God into a question that’s purely scientific, that Americans really do feel that evolution impinges on faith.  Proft has to drag the Pope in here to support his answer, but at least he admits that humans have evolved from other creatures.  But Pope John Paul also believed that at some point between Australopithecus afarensis and Homo sapiens, the good Lord injected hominins with a heritable soul.

— Jim Ryan: “Evolution is a reasonable theory. Regardless of the extent of its truth, I believe that God was ultimately responsible for our creation and infused human beings with a soul.”

Damn, this answer is dreadful.  “Reasonable”?  “Regardless of the extent of its truth”? A complete cop-out, topped up with pandering to the faithful.

— Bob Schillerstrom: “I accept the theory of evolution. There is compelling scientific evidence to show that evolution does occur. I also believe science and religion answer life’s questions in complementary ways.”

The first two sentences are GREAT — unusual sentiments for a Republican.  But then he takes the NOMA stance.  Well, I guess you can’t expect more than this from the GOP.

And now the Democrats:

— Dan Hynes: “I accept the theory of evolution.”

What a good answer!  Why can’t more of our candidates give a simple answer like this?

— Pat Quinn: “I believe that the scientific theory of evolution is the best explanation we have for the origin and diversity of species on Earth. As a Catholic, I do not see any discrepancy between my acceptance of widely held scientific principles and my faith in God as the prime mover of the universe.”

A bit NOMA-ish in the end, but at least he buys evolution.

Scores:  Republicans 1/7, Democrats 2/2. No surprise here. Republicans are a miserable God-fearing and Darwin-denying lot.

h/t: Alan Grohe

It’s not yet Caturday, but it’s New Year, and so I proffer the thirty best cat videos 0f 2009. There are many old favorites here, and some new ones. Here’s curmudgeonly Jupiter:

This is worth a quick note, both for the new methodology and the mildly interesting results. A new article in Proc. Nat. Acad. Sci. USA reports the use of sedimentary ancient DNA (“sedDNA”) analysis to show that both the wooly mammoth and the horse survived in North America several thousand years later than previously thought.  (Horses, which evolved largely in North America, went extinct around time that humans arrived here from Asia, and were later re-introduced in domesticated form by colonizing Europeans.)

Using fossils to determine when a species went extinct always yields a date older than the target date, for it’s unlikely that the latest fossil is from the last remaining population (this phenomenon is known in paleobiology as the Signor-Lipps Effect).

To get a better handle on extinction of the North American megafauna, Haile et al. simply extracted DNA from the permafrost at a site on the Yukon River floodplain in central Alaska, and, by sequencing, assigned it to various animals groups that became extinct.  By correlating the DNA sequences with the date of the permafrost layer from which they were taken, the authors could determine the most recent time the carriers of that DNA lived. (Sediment dating was done by the measurement of optically stimulated luminescence [OSL], a recently devised way of using the luminescence of minerals to determine when they were last exposed to sunlight.)

Halle et al. found this:  both horses and mammoths persisted in Alaska up to a time between 10,500-7,600 years b.p.

This is several thousand years later than the previous “extinction dates” based on fossils themselves, about 13,000 and 14,000 years b.p. for mammoths and horses, respectively.

What does this mean?  Well, the earlier coincidence between fossil-based extinction of these large beasts with the arrival of humans in North America (about 14,000 years b.p.) had led to the conclusion that humans quickly hunted these beasts to death, or that they went extinct due to rapid climatic changes during the late Pleistocene.  It could still be true that the extinction of these beasts was promoted by humans, or by climate, but that this didn’t take place so quickly after human contact.  As the authors say,

. . .the sedaDNA evidence for mammoth and horse persisting into the Holocene in interior Alaska is incompatible with such rapid extinction and indicates that late-surviving mammoths in the New World were not confined to islands in the Bering Sea that might have afforded protection from human hunters (10, 34). The protracted survival of mammoth and horse is also inconsistent with the hyperdisease hypothesis (5) (which requires their swift demise following human contact) and with megafaunal extinction due to end-Pleistocene environmental changes associated with abrupt climatic events (35), altered vegetation patterns (2), or intense wildfires sparked by a presumed extraterrestrial impact (6, 7).

Here’s a nice graphic from the paper:

Fig. 1. (caption taken from the paper): Stratigraphic profile and location (see inset map) of the Stevens Village site. Elevation is height in meters above river level, and age ranges (in calendar years) are shown at the 95 and 68% confidence intervals for radiocarbon (¹⁴C) and OSL, respectively. OSL ages were obtained from quartz sediments and ¹⁴C ages from plant macrofossils. Inset photo shows detail of buried vegetation (with arrow at shrub root) and lateral continuity of paleosol at 5 m elevation. The mammalian taxa identified from sedaDNA sequences are shown by symbols, with the scientific names given in Table 1.

I’m not a paleobiologist, nor an expert in dating, but the authors did deal with several possible problems, for example  the objection that older DNA could simply have been washed into younger sediments.

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Haile, J. et al. 2009.  Ancient DNA reveals late survival of mammoth and horse in interior Alaska. Proc. Nat. Acad. Sci. USA.  106:22352-22357.