Tuesday Crustie: Massive damage!

How could I miss a crustacean meme?

In 2006, Sony announced a game that was based “battles which actually took place in feudal Japan.”

And the very next words were: “So here’s this giant enemy crab.”

More on publisher of proposed Texas teaching supplements with intelligent design

Maybe the superficiality of this story in The International Business Times could be because it’s not a story about business. It’s a story about proposed supplemental materials that have intelligent design materials (which I wrote about here). The story does have some new information: the publisher is all of one person.

One submission has come from a company called International Databases, LLC. It's a one-man operation run by Stephen Sample, who says he has a degree in evolutionary biology and taught at the high school and junior college levels for 15 years.

I wish there was more reportage here. He “says” he has a degree in evolutionary biology. How advanced is the degree? Couldn’t someone check? It makes a difference if this is someone with a bachelor’s degree in biology versus someone with a doctorate. Few undergraduate programs are specifically for evolutionary biology at the level; most are “biology.”

Those sections say the “null hypothesis” is that there had to be some intelligent agency behind the appearance of living things. It is up to the scientists proposing a naturalistic explanation to prove their case.

Sample seems to be confused with the concepts of a null hypothesis with burden of proof. A null hypothesis is used in a specific experiment, which the origin of life is not.

As for “burden of proof,” the normal rule is that the burden of proof is on the person making the more extravagant claim. Following Sir William of Occam’s principle that the explanation with fewer entities is the more conservative one, the burden of proof would fall on someone who claims the origin of life is due to natural forces plus an unspecified intelligent agent (two entities), not the person invoking natural forces (one entity):

Ordinarily teaching from a religious perspective is forbidden in public school science classes. The principle was decided on in the Kitzmiller v. Dover, in 2005, when a judge ruled that teaching the theory of "intelligent design" was actually a form of religious instruction and therefore not allowed in public schools.

Not quite. The legal judgements against teaching religious points of view in science classes goes way back before Kitzmiller v. Dover. American Supreme Court cases go back to 1968. The National Center for Science Education has an excellent round-up of such cases.

Sample says the "null hypothesis" is such because the old experiments that attempted to produce "building blocks" of amino acids failed to do so.

The facts here have been mangled by someone, although it’s not clear if Sample or the reporter is doing the mangling. It seems to be a reference to the so-called “Miller-Urey experiments,” which succeeded in making amino acids.

Sample says it isn't stealth creationism - he says the intelligent agency might just as well be aliens.

Every intelligent design advocate that I have seen follows, “It could be aliens,” with, “Although I personally think it’s God” when pressed. There are vast reams of writing about intelligent design being compatible with certain theistic religions, particularly Christianity. There are no serious discussions in the intelligent design community that I have read that seriously discuss extraterrestrial intelligence. This is probably because the “aliens did it” hypothesis doesn’t solve the origin of life, but moves it off of Earth.

But he emphasizes that he wants students to learn to think critically, and that unlike the physical sciences, there aren’t any experiments you can do to demonstrate evolutionary theory.

If I’m generous, Sample might mean that there is no single experiment that can “prove” evolutionary theory, which is true. But science deals in evidence, not proof. And there are large numbers of experiments that have demonstrated evolutionary theory. You wouldn’t recreate all-female lineages of lizards in the lab without deep evolutionary thinking, to give just one recent example.

Additional: Sample is also silent on what experiments one could do to demonstrate intelligent design.

Is your research future predicted by your supervisor’s research past?

At the end of last week, I published a bit of a rant. After I had cooled a bit, I wondered if the response of my gut would survive scrutiny by my head.

The NeuroTree website says:

Big families stay big. Children of researchers with many offspring tend to have many offspring of their own.

This suggests a “pedigree” effect that many would see as positive (more students means more success). They don’t give the data supporting that claim, though.

I went looking for research on the effect of “pedigree.”

Goodwin and Sauer have a paper that sort of addresses the issue, although (1) it’s about economists, and; (2) they rated the prestige of the institution where a person got their doctorate, not the specific mentor (I suppose “lab” doesn’t have much meaning in business school). They find economists who received a degree from a “top 20” doctoral program gain a significant advantage in research productivity.

In contrast, a slightly newer paper by Long and colleagues (looking at management professors in business schools this time) found no effect of where someone got their doctorate, which seems to be evidence against “pedigree” being a useful predictor. Much more important to productivity was the quality of the institution where the faculty member was ultimately employed.

Williamson and Cable, again studying management faculty, found a positive correlation of productivity of doctoral supervisor with early career productivity. The more productive your boss, the more productive you are. Because it looked at the supervisor, not the program or institution, it seemed to be the closest to what I was looking for.

But the trail dried up for me when I went looking for similar data in the biological sciences. I’m sure there are papers out there, but I couldn’t find them very easily. If anyone knows any, I’d love references.

Evidence suggests that “pedigree” is an predictor of success. I was wrong.

I stand by my dislike of the term, however, with all the negative connotations that it has. “Pedigree” implies your past defines you. I prefer the term “heritage,” which recognizes that you are shaped and influence by your past, but are not necessarily defined by it.

References

Long RG, Bowers WP, Barnett T, White MC. 1998. Research productivity of graduates in management: Effects of academic origin and academic affiliation. The Academy of Management Journal 41(6): 704-714.

Goodwin TH, Sauer RD. 1995. Life cycle productivity in academic research: Evidence from cumulative publication histories of academic economists. Southern Economic Journal 61(3): 728-743.

Williamson I, Cable D. 2003. Predicting early career research productivity: the case of management faculty Journal of Organizational Behavior 24 (1): 25-44. DOI: 10.1002/job.178

Academic pedigrees

Academia is a meritocracy, where the only thing that matters is your own output, hard work, and skills. Ideally.

I hate being reminded of how far away from the ideal the reality is. The term “academic pedigree” is one of those reminders.

I understand the interest in looking for connections between academics. I’ve written about my own a few times, most recently here. What I dislike is that this is seen as some sort of meaningful yardstick for judging a person’s suitability for jobs, particularly tenure-track jobs. Indeed, I’ve read at least one post somewhere saying that pedigree was the most important factor.

Do people not think that discussing job candidates and grad students and post-docs using the same terminology as livestock and show dogs is not just a little demeaning?

“Pedigree” also has connotations with aristocracies. And one of the bad things about aristocracies is that they often set things up to keep all the power to themselves. Aristocracies often want preserve the status quo and making sure the playing field never becomes level. Because when it’s all about breeding, well, there’s nothing one can do about that, now, is there?

How would the discussion change if every time someone talked about “academic pedigree,” it was replaced with “well connected in the old boys’ club”? Let’s make it explicit that this discussions of pedigree are discussions about power relationships, and not merit.

Related posts

Inclining the playing field
Balkanizing small universities
To have and have not. Mostly not.

External links

Reason No. 52 not to go to grad school
Science professor - see the comments

Hat tip to Dr. Micro O.

Dog pedigree by ronmichael on Flickr; cow pedigree by dan mogford on Flickr; both used under a Creative Commons licence.

Personal statements and “I-don’t-know-what-is-it-but-I-like-it”

Imagine you were going to listen to a bunch of new songs. Could you tell me which songs you would like before you heard them?

You could probably make some good guesses, in broad strokes. “I like jazz, but I’m not very into country.”

But it starts to get very unpredictable at the level of individual songs? Even for my favourite artists, for songs I know well, I couldn’t tell why this song works for me so much better than that one.

There isn’t a formula to predict what songs are going to be global worldwide hits, and which ones are going to find an audience of maybe a few thousand. The small audience may love their song as passionately as the large audience loves the global hit. But the only way to tell which is which is to put it out there to the masses.

I realized today that personal statements, which we use so much for things like grad school applications, are like that for me. I can often pinpoint why I don’t like something retroactively, but I can’t easily articulate the common features in ones that I like.

This is frustrating for me as a teacher and grad program coordinator. I teach biological writing to my undergraduates, and I always have them do personal statements. It’s always the students’ favourite assignment. They find it useful. I try to help students who want to apply to grad school.

It’s as difficult to explain to people what will make a successful personal statement as it is to explain to them what will make a hit pop song. The things I can explain to people are very general – like saying, “Accordion songs are not likely to be huge hits.”

Of course, for students, it may be a revelation that they may have to put away the accordion if they want to reach a large audience. But I wonder how much more can be conveyed on the subject.

Photo by Irregular Shed on Flickr; used under a Creative Commons license.

The Zen of Presentations, Part 40: Lighting a fire under speakers

Ignite! talks rock.

We have a seminar class in my department, which all our majors must take. Normally, this class meets an hour a week, and every student gives one 15 minute talk, with 5-10 minutes for questions.

The problem is, each presentation becomes very high stakes, with no opportunity to try again. If you screw up once, you’re done. I wanted to give everyone a second crack at giving a talk, so I decided to have everyone do two talks: a 12-15 minute one, and an Ignite! talk.

The Ignite! format: You have five minutes flat. 20 slides, auto-timed for 15 second each. Then you sit down and shut up. Somewhere I saw the Ignite! motto was something like, “Enlighten us, but make it snappy.”

Across the board, my students’ Ignite! talks were head and shoulders above their long talks.

When I said this on the last day of class, I say a lot of heads nodding in agreement. So it wasn’t just me; many people thought these talks were better.

There were many differences between the long and Ignite! talks. For the long talks, I banned PowerPoint and I picked the topic (these were both intended to push students out of their comfort zone). But I don’t think those were why the Ignite! talks were better.

They were better because of the energy everyone brought to their talks.

Faced with 15 second per slide, people had to know their story, had to concentrate, and absolutely no dawdling! That meant every speaker had to crank it up, and it was so much more fun to watch overall.

And even if it wasn’t great, you knew you wouldn’t be stuck listening to a crummy talk for more than a few minutes.

Not only am I sold on the value of doing these for my students, I would love to see more academic conferences try Ignite! sessions. You can get a surprising amount of information out there in five minutes if you plan it right. It could leave a lot more time for the things that people like the most, which are the meetings in the hallways and over coffee.

If you haven’t done one, try it! The format lives up to its name.

External links

Presentation Zen: The Ignite presentation method
Speaking about Presenting: The fastest Way to create an Ignite presentation (several students told me this was very useful to them)

Tuesday Crustie: Know that I glory in this nose of mine

I was pleased that people liked last week’s description of a new squat lobster and its whimsical name, Uroptychus pinocchio. Today, let me introduce its cousin, another  species new to science with an equally choice nom de science:

Like its relatives, Uroptychus naso and Uroptychus pinocchio, this new species lives in the western Pacific. These three are distributed from Japan in the north down to Australia in the south. Something interesting happens as you travel along this way on the various islands: the species of plants and animals that you find seem to change suddenly as you go south. This transition point is now called Wallace’s line, after the naturalist and co-discoverer of natural selection, Alfred Wallace, who noted this.

But do you get similar effects in ocean species? These squat lobsters do line up in a way that is reminiscent of Wallace’s line: the new species are at the north and south end of the range. Even the better known U. naso, which is more widely distributed, has some populations that appear to be rather isolated from the main lineage.

These squat lobsters are live several hundred metres down. The geologic history of the ocean bottom in creating the shelf zones they inhabit may be as important for the distribution of some of these species as the geological history of the islands are for the distribution of these terrestrial species.

The name of this second new species? Like U. naso and U. pinnochio, this species’ name celebrates its prominent rostrum.
 
Uroptychus cyrano, after the famed French poet and swordsman.



Reference

Poore GCB, Andreakis N. 2011. Morphological, molecular and biogeographic evidence support two new species in the Uroptychus naso complex (Crustacea: Decapoda: Chirostylidae)  Molecular Phylogenetics and Evolution: In press. DOI: 10.1016/j.ympev.2011.03.032

Carnivals for May 2011

Encephalon #86 is hosted at Forensic Pscyhologist. By the way, this carnival needs hosts for the next couple of months! Check out here if you want to contribute.

The carnival of Evolution #35 is hosted by Lab Rat.

Circus of the Spineless #62 is now available at Squid a Day.

Want us to teach more?

Ronald Trowbridge, writing in the Texas Tribune, thinks public universities in Texas should be teaching more and doing less research.

Our universities have shifted priorities to research first, students second. “The ultimate source of this cultural shift,” writes Harry Lewis, a former dean at Harvard University, “is the replacement of education by research as the university’s principal function.”

But Trowbridge doesn’t examine the reason for that shift. I suggest that this shift may have occurred because there is money to be had through research. Successful research programs are a revenue source. If Texas politicians and taxpayers want more teaching, they should be willing to pony up the cash that will replace the money that will be lost as less research is done.

Trowbridge also bemoans the number of adjuncts and graduate students teaching introductory classes. I agree; I’d love to see more tenured and tenure-track faculty teaching such classes. Again, who’s willing to pony up the cash for those more permanent positions?

Trowbridge argues that professors teaching two classes a semester is normal, when this is only true at the two major institutions in the state. He also apparently doesn’t consider working with research students “teaching,” when it is arguably some of the most important teaching at a university.

I’m for transparency and accountability, but “accountability” is not a license to allow you to demand the outcomes you’d like.

Comments for second half of April 2011

Cephalove talks about why octopuses are “honorary vertebrates” in European animal care regulations.

Christie, I’m so disappointed.

Prof in Training wonders about authorship credit for students. Much discussion ensues. Hey! A lot more people should read my letter in Science about this.

Prof-like Substance wanted people to promote their blogs.

At The Meandering Scholar, BrooksPhD asks what people do for their scientific societies. And why don’t people do more?

A note to those in high school

I thought about what I liked in high school, and realized...

Choose what you like in high school well. It’ll be with you a lot longer than you think.


It is sad how little progress I’ve made.

Flight of the dodo

Contrary to popular belief, dodos can fly.

They just have spectacularly bad luck in their flights suffering from looooooooong delays.

Yesterday, Randy Olson (blue shirt, above) was on our campus, talking about science, filmmaking, evolution and much more. He was here as part of a program by the Office of Graduate Studies.

We had hoped he would arrive on Tuesday to make the screening of Sizzle: A Global Warming Comedy, but he got stuck in Houston for almost an entire day. Ironically, he had been in San Antonio before that, and could have driven here faster than his flight turned out to be!

The audience reaction to Sizzle was very positive, and myself and my colleagues did a bit of discussion afterwards.

Randy and I finally met at a screening at Cine El Ray, where we saw a screening of Innocent Voices. There was a bit of discussion about both the movie and Randy’s work afterwards.

Wednesday was the big day, with a workshop with our Teaching Academy on communication, followed by viewing some student and university videos, an informal session, and finally a screening of Flock of Dodos.

In the Q&A after the screening, Randy talked a little bit about his next film project, which will feature what many people say is their favourite part of both Flock of Dodos and Sizzle:

Randy’s mom, Muffy Moose, now 87.

If you saw Flock of Dodos, you saw a little bit of the life history of Randy’s parents near the end of the movie. Muffy was born in the Philippines, met Randy’s father there, and was shipped out on the eve of the war, where she became a model. His father was a survivor of the Bataan Death March. The film will be about the history of the Philippines in World War II, viewed in part through Muffy’s experiences.

The working title is Muffy’s War.

The day for me ended with a geeky fanboy moment. I got my copies of Don’t Be Such A Scientist and Flock of Dodos signed.

Cosmic coincidence department: We learned that his cameraman on the highly-viewed Science Cheerleaders video (which I wrote about here), Brandon Garcia, was one of our students! He friends with several of the grad school staff, including Denisse Cantu (far left in top picture).

Review: Written in Stone

I expected this book to be about the fossil record, but it’s more accurate to say it’s the record of the fossil record.

By which I mean this:

Each chapter covers one animal group, usually (but not always) that has undergone a major transition in form. Land mammals to whales, fish to tetrapods, and dinosaurs to birds are all featured. The narrative of each chapter, however, follows the history of the science rather than the science of the history.

There are wonderful stories here that I had not heard before, and the characterizations of the scientists themselves are rich. These were the book’s greatest strengths for me. I particularly enjoyed the description of the showmanship of Albert Koch, who tidied up with his spectacular (though rather dubious) whale skeletons in the mid 1800s.

The book is illustrated, but the illustrations are rather small. They are often old woodcuts with a lot of fine detail, but because of the creamy colour of the mid-grade paper, it’s often a bit difficult to make out some of the detail. The typesetting itself is also a touch on the small and dense side, again making the book feel like a more difficult read than it actually is.

As I read Written in Stone, though, I kept wondering, “Who is this book for?”

It’s likely tough going for a reader without a university degree. The discussions often run into some rather technical discussions of anatomy. Maybe an undergraduate with a comparative vertebrate anatomy class under her belt might be less flummoxed than me, but I often found such sections tough going.

It’s not exactly for people who are looking for how the fossil record provide evidence for evolution. Other books, like Jerry Coyne’s Why Evolution is True, lay out that evidence in a more straightforward way.

It’s not for invertebrate fans. Despite the ammonites on the cover, most of the chapters are about vertebrates. Now, I love me some charismatic megafauna, but the invertebrates aren’t given their due. On many key issues of interpreting the geologic record, understanding the pace of evolution, and documenting extinctions, the backbone of evidence is provided by invertebrates (pun intended).

It seems like Written in Stone is for people with undergrad degrees in biology who never got much instruction about fossils in their career. Alas, that audience is larger than I would like it to be.

During graduate students’ oral examinations, I often ask them, “How old are the oldest fossils on Earth?” Few master’s candidates give me a decent answer. And I picked that question because I once read that it is one that a high school graduate should be able to answer.

I wouldn’t recommend this book to just anyone. It’s a book that I would recommend enthusiastically to some people (if I knew them reasonably well). It will reward many readers handsomely.

Reference

Switek B. 2010. Written In Stone. Bellevue Literary Press, pp. 1-320. ISBN: 978-1934137291

Tuesday Crustie: What a happy lad since the day he lost his strings

Squat lobsters are not terribly well known, and this is a new species in a genus that even I didn’t know about: Uroptychus.

This species is being split off from Uroptychus naso (“naso” means nose), which is found in the western Pacific. The new species was spotted because of genetic surveys. Two lineages of mitochondrial DNA were found in samples, which prompted a closer look at what had been thought to be a single species.

Once they had spotted the genetic difference, the authors went back and tried to look for morphological differences. The authors describe these as “slight” - subtle variation in rows of setae and the like. And the authors describe two new species from the re-examination. It’s a nice example of how genetic work can lead to the discovery of cryptic species.

This one has a more northern distribution, ranging up to Japan. And it has a wonderful name, in reference to its relative, and its prominent rostrum.

Uroptychus pinnochio.

And people say scientists have no sense of humour.

Next week, I’ll showcase the other new species and talk a bit about the geography related to the three squat lobsters.

Reference

Poore GCB, Andreakis N. 2011. Morphological, molecular and biogeographic evidence support two new species in the Uroptychus naso complex (Crustacea: Decapoda: Chirostylidae). Molecular Phylogenetics and Evolution: In press. DOI:10.1016/j.ympev.2011.03.032

Publishers submitting intelligent design materials for consideration in Texas

Despite that evolution is the law in Texas, intelligent design keeps cropping up with regards to the state K-12 education.

The Texas Freedom Network is reporting that applications for instructional materials for Texas classrooms include intelligent design materials; in particular, they mention International Databases. The Texas Education Agency has material from this publisher online, but it is password protected.

If the Texas Freedom Network’s information is correct, these materials are unsuitable. This example is given:

Teacher instructions such as: “students should go home with the understanding that a new paradigm of explaining life’s origins is emerging from the failed attempts of naturalistic scenarios. This new way of thinking is predicated upon the hypothesis that intelligent input is necessary for life's origins.” (Module 8, “Teacher Resources,” Slide 3)

That’s about as blatantly religious as one can get without mentioning God.

It’s important to note that these are applications only. It doesn’t mean they will be approved.

Well, at least we’ll have something to talk about after Flock of Dodos screens on Wednesday.

A new refereeing format for peer-reviewed journals

Peer review currently consists of writing, and reading, lengthy critiques and recommendations and completed forms. Other refereed activities have developed a much faster, more concise method of communication that journals would do well to consider adopting. (Click to enlarge.)

Inspired by philosophy referee hand signals.

Credential evaluation

“Strong support for the argument that video game violence is indeed harmful.”

What would that strong support be? According to this story, it’s whether authors have published a scientific paper about media violence.

Read that carefully. It’s not about scientific papers on media violence, it’s about the authors of scientific papers on media violence.

Here’s the deal. There’s a court case. California wants to be able to ban the sale of video games to people under 18 based on the violence content. People get to file amicus briefs to offer their opinions for the court to consider. The authors of this study decide to look for evidence that video games cause violence by examining the scientific credentials of who wrote the court briefs.

They compared whether the amicus brief authors had published papers about media violence. Again, they’re not saying anything about the papers, just whether a brief author has written any in that area. In theory, someone who published a study on media violence that showed no effect, but who argued in favour of the proposed laws, you would be counted on that side, even if your research didn’t support a link. (Admittedly, that seems unlikely.)

In both sides of the case, authors with published scientific articles on media violence are in the minority. Those arguing the side claiming that violent video games are not problematic have a smaller percentage.

Still, most of the people writing briefs don’t have scientific expertise on the subject, which in and of itself is worrying.

But is comparing the percentages valid at all? Who decides who gets to submit amicus briefs? If briefs are submitted voluntarily, there could be any number of biases in the generation and selection of briefs.

Another piece of evidence that is considered “strong support” is by analyzing the impact factor of the journals the brief authors have published in. Impact factors have many problems, but their use here is weird. Again, the authors are not examining the impact factors of journals that published articles on media violence (as far as I can see), but whether the amicus author had published in high impact journals, ever.

Sorry, but that is not “Strong support for the argument that video game violence is indeed harmful.” It’s barely support at all. If they had said, “Supporters for laws limiting violent video games have more expertise than those opposing such laws,” there would be no problem.

It would have been better to look for peer-reviewed articles cited in the briefs. Than start rating those articles for the quality of their evidence, using basic criteria like:

• Is the paper actually about video games? (I.e., is it relevant?)
• Was it a randomized, double blind experiment?
• How big was the sample size?
• How big was the effect size?
• Has the finding been replicated?
• How often has the paper been cited?

Credentials are important, but they shouldn’t be a substitute for evidence.

Caveat! The paper that this research will be described in will not be published in May. It is possible that the actual research is better than the story in Science Daily (which I’ve been baffled by before).

Hat tip to Julie Dirksen.

Extra extra DNA in giant neurons of slugs

You have two copes of your DNA in almost all your cells. The notable exceptions are your sperm (if you’re a guy) or your eggs (if you’re a gal). So if you measured the DNA in a cell in your body, you should get the same amount in any cell, regardless of the type of cell or the size of the cell.

Many molluscs, like Limax maximus here (same genus, different species than used in this research) have big, honkin’ neurons. This is what has made some slugs, particularly Aplysia californica, valuable animals to people who want to record the electrical activity from neurons. Somewhere along the way, someone measured the amount of DNA in Aplysia, it seemed suspiciously high.

There are many ways that you could end up with large amounts of DNA in a cell. The cell might form from several smaller cells that have been fused together (this happend in some giant axons in squid). An alternative hypothesis is that the neurons have extra DNA because the DNA has replicated without the cells dividing.

Yamagishi and colleagues tries to test this using slug. Reasoning that the effects they were seeing were related to regular growth, they fed one group of slugs a lot of food, the controls slightly less, and starved a third group for a few weeks. At the end of this, they successfully grew groups of slugs that differed in the size of:

• Their bodies;
• Their brains;
• Specific regions within the brain, and;
• Individual giant neurons in the brain.

That bigger bodies mean bigger brains is not unusual; this is a well-known scaling effect. It’s also not surprising that the main cause of the size increase is in the size of existing neurons, rather than increased numbers of neurons, because most invertebrates seem to have fairly rigid numbers of identified neurons across a wide range of sizes.

The authors are most interested in whether these extra giant neurons in the well fed animals also have additional DNA (they do) and how it gets there. To test this, they added a dye called BrdU that will show up in cells that are actively making DNA. Usually, this means in cells that are actively dividing.

This is one of the critical pieces of evidence, showing BrdU-labelled neurons in the subesophageal ganglion, with the starved animals on the left and the overfed animals on the right:

This is the full sized picture as it appears in the journal. It’s almost impossible to make out the actual, crucial data points on the right side instead of the profusion of arrows. In the PDF, you can zoom in rather large and convince yourself those data points are there... but by jove, you shouldn’t have to go to that trouble.

It’s also a bit puzzling as to why the normally fed control group isn’t in many of these comparisons.

This all suggests that the neurons are undergoing mitosis (genetic duplication) without cytokinesis (physical separation of the cells). This might be happening because neurons are metabolically very active. They have to synthesize and transport all their proteins quite long distances from the nucleus. And because the number of cells doesn’t change much in invertebrates, growth could put significant demand on a cell’s ability to deliver enough material.

That said, it isn’t a simple relationship. You would expect that because muscles vary tremendously with body size, motor neurons would show this tendency to have more DNA more than, say, interneurons. But that turned out not to be the case.

It’s not clear from these experiments if the neurons are duplicating the entire genome in the cell, or whether they are being more selective, and only duplicating key components – particular chromosomes, say.

It’s also not clear how the signals of more food and more growth gets picked up by the neurons and turned into a signal to make more DNA.

That this was all tipped off by an observation in one species and confirmed in another suggests that this is widespread among molluscs. But would it be expected in other species, too?

I prediction that this loading up large neurons with DNA will be found in other invertebrate, but will be rarer in vertebrates. Arthropods and some worms also have giant neurons and stereotyped numbers of neurons, so they would seem to be facing the same problem as molluscs. Vertebrates seem to have more variable numbers of smaller neurons, so I would expect it to be more rare there.

Reference

Yamagishi M, Ito E, Matsuo R. 2011. DNA endoreplication in the brain neurons during body growth of an adult slug. the Journal of Neuroscience 31(15): 5596-5604. DOI: 10.1523/JNEUROSCI.0179-11.2011

Picture by rhonddawildlifediary on Flickr; used under a Creative Commons license.

Science 3.0 neuroscience blogging contest

Science 3.0 is sponsoring a neuroscience blogging contest, for both new and old posts. You have to scroll down to find the entry form, on the right hand side.

Education can set people free, in more ways than one

I’m a bit behind on my podcasts, but I had to point to this one from All in the Mind about a week and a half ago, about why people kill.

I found this piece from guest James Gilligan completely fascinating:

When I was directing the mental health services for the Commonwealth of Massachusetts in the United States we did a study to find out what program in the prisons had been most effective in preventing re-offending or recidivism after prisoners left the prison. And we found one program that had been 100% successful over a 25-year period with not one of these individuals returning to prison because of a new crime.

And that program was the prisoners getting a college degree while in prison.

You know, when you’re an educator, it’s easy to be so bogged down in the day to day routine of marking and managing students and preparing assignments that the idea that education can be transformative is something that you just give lip service too.

It takes something like that to make you realize that education truly can transform people for the better.