How parasites manipulate hosts

December 5, 2012 • 11:52 am

If you want to see the latest scientific skinny on how parasites manipulate hosts (e.g., the fungi and flukeworms that turn ants into “zombies”), you can’t do better than read this special issue of The Journal of Experimental Biology: “Neural parasitology: how parasites manipulate host behavior.” And all of the articles are free!

I’m always amazed that so-called “simple” organisms like fungi and flukes can affect host behavior in complex ways that facilitate the parasites’ reproduction. This is one of the great unknown areas of biology that will eventually yield to patient investigation.  What chemicals do they produce that can, say, force an ant to climb a tree trunk, dig its mandibles into the trunk, and at the same time turn its abdomen red (like a berry) and weaken the junction between abdomen and thorax, so that a hungry bird will spot the parasite-filled abdomen, mistake it for a berry, nom it, and then allow the parasite to continue its life cycle in the bird’s digestive tract? There must be interesting chemicals involved! You can read about that story here, and here’s the unfortunate ant:

A parasitie nematode has killed this ant but also changed it to make its abdomen resemble a berry, facilitating its ingestion by the next host, a bird
A parasitic nematode has killed this ant but also changed it to make its abdomen resemble a berry, facilitating its ingestion by the next host, a bird

But there are many other cases like this. Here are a few of the JEB articles with links, but see the full table of contents for more.

 HOW PERNICIOUS PARASITES TURN VICTIMS INTO ZOMBIES
Kathryn Knight
J Exp Biol 2012 216:i-iv. doi:10.1242/jeb.083162

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Editorial
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 Neural parasitology: how parasites manipulate host behaviour
Shelley A. Adamo and Joanne P. Webster
J Exp Biol 2012 216:1-2. doi:10.1242/jeb.082511
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Alteration of host behaviour
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Parasites: evolution’s neurobiologists
Shelley Anne Adamo
J Exp Biol 2012 216:3-10. doi:10.1242/jeb.073601

An overview of parasite-induced behavioral alterations – and some lessons
 from bats
Janice Moore
J Exp Biol 2012 216:11-17. doi:10.1242/jeb.074088

Parasite manipulation of host personality and behavioural syndromes
Robert Poulin
J Exp Biol 2012 216:18-26. doi:10.1242/jeb.073353

h/t: Matthew Cobb

Bill O’Reilly: Christianity is not a religion, but a philosophy

December 5, 2012 • 9:54 am

Bill O’Reilly, an infarction waiting to happen, was arguing with David Silverman, president of American Atheists, about the secular “War on Christmas.” In a moronic attempt to defend himself, O’Reilly claimed that Christiantiy is not a religion but a philosophy. (He does admit, though, that Roman Catholicism and Judaism are religions!)  O’Reilly’s stupid statement is embedded in this clip from the David Parkman show, and Parkman comments, “Since when do we give federal holidays for philosophies?”

Too, if O’Reilly is right, the government should immediately remove all tax exemptions for Christian churches.

h/t: Haggis

James Shapiro, in his attempts to forge a new evolutionary paradigm, is reduced to going after my commenters

December 5, 2012 • 5:42 am

My Chicago colleague James Shapiro appears to have been badly stung by my repeated criticisms of his attempts to forge a new evolutionary view based on the “self-engineering” of organisms and their DNA (see here,  here, here, and here, for instance).

This will be the last time I comment on Shapiro’s PuffHo pieces, as I don’t want to give him the attention that, as someone who wants to be seen as the founder of a new evolutionary pardigm, he so desperately wants.

Let me just point out Shapiro’s Big Error (also committed by those who approve of his PuffHo piffle) one more time. It is not rocket science, and even non-scientists should be able to grasp it. I’ve put it in bold so Shapiro and his followers will take note:

Regardless of the source of genetic variation, if new variants are to become “fixed” (i.e. ubiquitous) in natural populations after they arise, and to become part of complex adaptations, there is no credible alternative to natural selection for the process causing that fixation.

Like some molecular biologists, Shapiro repeatedly mistakes the source of genetic variation creating new “mutations” with how that variation comes to predominate in a population. He thinks that the former explains the latter, ergo that natural selection plays a very small role in evolution.  And yes, we now know of a world of “mutations” undreamt of by earlier geneticists, including horizontal gene transfer (especially important in bacteria), gene duplication, mobile genetic elements, and the like.  But what happens to variation generated by these processes depends on whether they give a reproductive advantage to the organism.  If they don’t (i.e., natural selection doesn’t favor the variant), they get eliminated from populations.  If they do, they get fixed.

It’s still natural selection, Jim. Why do you fail to understand that?

(Let me add right away that I accept other mechanisms of evolution such as genetic drift, which is certainly of importance in much molecular evolution. What I’m talking about here are complex adaptations, not only of morphology [e.g., the heart], but also complex molecular mechanisms like DNA repair or the immune system.)

Sadly, in his latest PuffHo piece (really, does the science section even look at what’s appearing on their site?),”Inconvenient truths: why are some self-styled defenders of evolution so resistant to lessons from molecular genetics?“, Shapiro is reduced to criticizing two readers who have left comments on my latest critique of Shapiro’s Big Idea.  You’ll recognize their names if you’re a regular: Ben Goren and Torbjörn Larsson.

And Shapiro’s criticisms of both men’s comments are of the same ilk: the modern theory of evolution (“neo-Darwinism,” though I am going to stop using that label) is wrong because it doesn’t deal with “mutations” that aren’t simple changes in single nucleotides in the DNA. For a rebuttal of Shapiro’s thesis, just reread what’s in bold above. Horizontally transferred elements, transposable genetic elements, and the like, must be acted on by natural selection if they’re to become part of an adaptation.

I’m not a willy-nilly defender of my commenters, but in this case Goren and Larsson are right and Shapiro is wrong. Take, for instance, what Shapiro says about Torbjörn:

A second commentator, Torbjörn Larsson, argued that horizontal DNA transfer posed no challenge to the neo-Darwinian theory: “In other words the generic gradualism of Darwin mentioned in the article isn’t rejected by the observed degree of horizontal gene transfer.”

But Torbjörn’s claim does not make sense scientifically. Horizontal transfer is not the gradual Darwinian accumulation of changes. Horizontal transfer episodes rapidly incorporate complex evolved DNA structures into new genomes by coordinated molecular events.

There is no way we can reasonably apply the term “random mutation” to a DNA transfer process that utilizes dedicated surface structures for bringing two cells together, assembles a multi-protein DNA transport pore connecting the cells, and initiates DNA transfer replication at a specific site on plasmid DNA. [JAC: yes we can; for the transfer is a genomic change that occurs randomly!]

The well-established molecular details of horizontal transfer in the evolution of bacterial antibiotic resistance are difficult to reconcile with neo-Darwinism.

No they aren’t—not at all.

What Shapiro can’t see here is that it doesn’t matter how new changes in a genome come about: via classical base-pair “mutations” or by the more recently discovered processes of horizontal gene transfer (e.g. the movement of units of DNA from one species of bacteria to another via a virus vector). If those chunks cause antibiotic resistance in the recipient species, and there are antibiotics around, natural selection will go to work on the new “variant.” Indeed, this is how a lot of antibiotic resistance evolves in bacteria.  But it doesn’t matter how a variant arises: they are all equivalent to classical mutations and their dynamics can be described by the classical equations of population genetics.  After all, antibiotic resistance in bacteria is seen as a classic and easily-understood example of natural selection!

So no, there isn’t an insuperable problem here for “neo-Darwinsim.” We just have to expand our idea of “mutation.”

Shapiro can’t—or won’t—get this, and I give up on him. Time will tell if his “non-Darwinian” ideas gain any traction, but the fact that he propounds them at PuffHo rather than in peer-reviewed scientific journals (how about sending a piece to Evolution, Jim?) is not propitious.  As one of my friends, who is both an evolutionist and molecular geneticist, emailed me after reading Shapiro’s piece:

Part of his problem has always been the one that some molecular biologists have: they confuse molecular causation with evolutionary causation. All of the mechanisms mediating horizontal transfer and so forth that he cites are indifferent to their effects on fitness: adaptation still arises as a consequence of the sorting agency of natural selection.

I sometimes wonder if there is a polymorphism in the human population for ability/inability to see the distinction. Jim would then be an example of someone who got a really bad version of the mutant gene for inability.

I’ll let Ben and Torbjörn defend themselves, but for me Shapiro sleeps with the fishes.  He will go on crying in the wilderness that is the PuffHo science section until he leaves this earthly vale and his ideas fade into well-deserved obscurity.  I’ve made my point, and I’m done with him. I may seem “strident and militant” about this, but one reaches a point when fulminating ignorance, pointed out but not corrected—much less admitted—must be shown for what it is.

Even more unbelievable: Bristol University Christians ban women from speaking

December 4, 2012 • 2:39 pm

I hardly need add anything to this to show how barking mad Christians are—even when they’re the supposedly tame UK Christians. From the Bristol Tab via Damian Thompson’s website at the Telegraph:

Bristol University Christian Union have forbidden women from speaking at their weekly meetings.

The move reflects the recent decision by the Church of England synod to reject the introduction of female bishops, consequently ignoring the last century of the equal rights movement.

Having spent ‘a lot of time exploring this issue, seeking God’s wisdom on it and discussing it together’ the CU executive committee decided that it was no longer appropriate for women to teach alone at weekly meetings, or be the main speaker at the CU weekend away.

Women are now also banned from speaking alone at the group’s mission weeks.

However, it’s not all gloom and doom: women are allowed to speak as a double act with their husbands. Those who are unmarried must remain silent.

The Christian Union is presumably evangelical, but does that matter?

As one commenter at the Tab said, trying to justify this execrable state of affairs, the Union actually voted to allow women to speak, but limited that to certain settings.  Thompson notes:

I must say that, whatever the truth, it sounds as if the CU has some complicated policing to do. What if an unaccompanied woman’s conversation spills over in “teaching”? What if hubby steps out of the room at an “Equip” meeting and the wife carries on talking? Do they keep a gag handy?

Thanks, Church of England!  Why do all of you hate women?

Bristol University is a member of the “Russell Group,” a consortium of Britain’s top 24 public research universities.  This could never happen at an American public university, for it would immediately lose all government funding for sexual discrimination.

h/t: Pyers

The Pope tweets!

December 4, 2012 • 12:09 pm

Well, he hasn’t started yet, but I’m sure you’re all dying to follow Ratzinger when he begins his official pontifical tweets at this Twitter site. At last check he had over 369,000 followers even though there’s only a welcome message. Of course, the Pope himself ain’t gonna follow anyone (unless God tweets!):

Picture 2

According to The New York Times,

Benedict is expected to send his first post at a general audience at the Vatican on Dec. 12 — a response to questions about matters of the faith that he is now accepting via the hashtag #askpontifex, officials said.

The Vatican acknowledged that it had chosen the @pontifex handle not only because of its meaning but also because many other handles had been taken.

The move is aimed at drawing in the Roman Catholic Church’s 1.2 billion followers, especially young people. “The pope’s presence on Twitter can be seen as the ‘tip of the iceberg’ that is the church’s presence in the world of new media,” the Vatican said in a statement.

Just do not expect the pope to start following you on Twitter or retweeting your posts, Greg Burke, a former Fox News correspondent in Rome who was named a Vatican communications adviser this year, said at a news conference. “He won’t follow anyone for now,” Mr. Burke added. “He will be followed.”

Of course! But this raises the thorny status of the theological force of the messages.

Aides will write Benedict’s posts, but the pope himself will “engage and approve” the content. The pope will post messages however often he feels like it. . .

Asked whether the pope’s posts would be infallible, Msgr. Claudio Maria Celli, president of the Pontifical Council for Social Communications, laughed and said they would be part of the church Magisterium, or collective teaching, but should be considered “pearls of wisdom,” not exactly doctrine.

“In any case, it’s a papal teaching,” Monsignor Celli said. “The message is just entrusted to a new technology.”

What would you like to see the Pope tweet? Remember, you’re limited to 140 characters.

A bunch of us go after Nicholas Wade’s accommodationism in the New York Times

December 4, 2012 • 9:47 am

Last week I wrote a critique of Nicholas Wade’s specious prescription, published in the New York Times, for curing the rift between fundamentalists and those who accept evolution.

I faulted him on two counts. First, he blamed atheists for the persistence of creationism, mentioning “militant atheists like the biologists Richard Dawkins”.  Second, he suggested that scientists should characterize evolution as a “theory” rather than as a “fact”—an action that, he claimed, that would heal the rift by offering creationists a “fig leaf” to save (or cover) face. In his original piece, Wade wrote this:

By allowing that evolution is a theory, scientists would hand fundamentalists the fig leaf they need to insist, at least among themselves, that the majestic words of the first chapter of Genesis are literal, not metaphorical, truths. They in return should make no objection to the teaching of evolution in science classes as a theory, which indeed it is.

I objected to that because it plays straight into the hands of creationists by suggesting that evolution is “only a theory”—their most powerful rhetorical weapon. And why would calling evolution a “theory” make any thinking person (or unthinking creationist) be strengthened in believing the literalism of Genesis? Those people already believe it strongly! Wade is suggesting that scientists make a Devil’s bargain, and I won’t have it.

I couldn’t rest by just posting my response in this website, and so I wrote a letter to the New York Times’s Science editor. Today, on p. 5 of the “Science” section, they printed that letter (the first one below) along with several others and Wade’s lame response. Here’s a screenshot, since it doesn’t seem to be online (maybe they’re too embarrassed by Wade’s inanities); click to enlarge:

Picture 1

And, in regular print, my letter and Wade’s response (my original was severely edited for space: cut by more than 50%):

To the editor:

Nicholas Wade argues that creationists will be converted to evolution only when scientists “show respect for all religion.” That claim is patently false.  Organizations like BioLogos, founded by National Institutes of Health director Francis Collins, have spent many years and much money trying to turn Christian creationists toward evolution by “respecting their faith”.  It hasn’t worked.

Teaching that the book of Genesis is a metaphor, as Wade suggests, is anathema to fundamentalists since it implies that Jesus died for a metaphor—the original sin of a nonexistent Adam and Eve.

Reconciliation doesn’t change minds; reason and logic do.

Jerry A. Coyne
Chicago
Jerry A. Coyne is a professor in the Department of Ecology and Evolution of the University of Chicago and author of “Why Evolution is True.”

Wade’s response:

Nicholas Wade replies:

Was I too hard on Senator Rubio? Our politicians have to cope with increasingly complex and technical issues. If they do not distinguish between good science and nonsense, they will be without guidance and, as I said, rudderless. But the thrust of the article was to blame the unresolved war between fundamentalists and scientists for putting politicians like Mr. Rubio in such a difficult position.

As Rabbi Cahana suggests, creationists like to say evolution is “just a theory,” as if it were mere speculation. In scientific parlance, however, a theory is a vast intellectual edifice that explains and is supported by a large array of facts and scientific laws. Evolution is a theory in the latter sense only.

Still, many diplomatic treaties are written so the two sides can interpret critical terms in their own way and allow business to proceed. This is the basis for a compromise: let fundamentalists interpret the word “theory” as they wish and in return cease to oppose the teaching of evolution in schools.

I confess that I lack Dr. Coyne’s zeal for converting the creationists to Darwinism. Nor did I suggest it would be either possible or desirable.

What would be desirable is to get them to drop their opposition to teaching evolution in schools. That is a practical issue to be settled by negotiation. Unfortunately, the extremists on both sides are so fond of striking militant stances that the gap between them has only increased.

Most of the other letters also castigate Wade for misunderstanding what a scientific theory is, and I can’t resist highlighting Eric Schwaber’s letter, which is terse and to the point:

To the editor:

Admitting evolution is a theory won’t change anything. Gravity is a theory, but you don’t see fundamentalists jumping out of 10th floor windows. The problem here is not in the semantics of the discussion, but in the irrational refusal of empirical and scientific evidence by religious organizations.

Eric Schwaber
Medford, Mass.

In contrast, Wade’s “response” is a non-response, failing to deal with the substantive issues about how creationists use “theory” when characterizing evolution. Nor does he consider whether his suggestion would work (anybody who knows fundamentalists realizes it wouldn’t). He could have backed off, but remained intransigent.

What strikes me is his almost prideful statement that he “lacks Dr. Coyne’s zeal for converting the creationists to Darwinism.” (Note the words “zeal,” and “conversion” which implies militancy or even the religiosity of evolutionists. Wade could have said “enthusiasm”! And what’s wrong with trying to teach evolution?)

But fine—leave the “conversion” to the evolutionists.  But what’s really dumb is Wade’s suggestion that if we characterize evolution as a “theory,” the faithful won’t necessarily accept the factuality of that theory, but will stop opposing the teaching of evolution in public schools. What a ridiculous notion! If fundamentalists don’t accept evolution but see it as the Devil’s work, and themselves believe in creationism, what on earth makes Wade think that by characterizing evolution as a “theory”—but still teaching the evidence for it—creationists won’t try to stick their own noses in the tent? For make no mistake: any good science teacher is going to do more than say “evolution is a theory.” That teacher will show how it’s a scientific theory buttressed by innumerable facts.

Finally, the issue of teaching creationism in the schools is certainly not one “to be settled by negotiation.” There is no compromise that is desirable or possible: it’s an issue to be settled by legal battles and unrelenting opposition to the superstitions and lies of creationists.

And once again Wade uses the “atheists-and -fundamentalists-are-both-militant” trope:

Unfortunately, the extremists on both sides are so fond of striking militant stances that the gap between them has only increased.

This man is an embarrassment to that newspaper, which is rapidly becoming a haven for accommodationism.

And that statement, of course, brings to mind the famous xkcd cartoon:

atheists

h/t: John Brockman for the scan and alert