Genetic Load, Neutral Theory, and Junk DNA

The average human newborn has about 130 new mutations that were not found in either parent [Mutation Rates]. These mutations accumulate as a natural result of errors in DNA replication between the time that the zygote is first formed and the time that the sperm and egg cells are produced for the next generation.

A species cannot afford to accumulate deleterious mutations in the genomes of its individuals. Eventually the number of "bad" mutations will reach a level where most genes have multiple "bad" alleles and it becomes impossible to produce offspring.

This phenomenon is referred to as genetic load. It means that species can only survive if the genetic load is below some minimum value. A good rule of thumb is that there can't be more than 0.1 deleterious mutations per individual per generation but in actual populations this value can be a bit higher. [UPDATE: This should be one (1) deleterious mutation per generation.]

How do you reconcile this with the known mutation rate in humans? If there are, on average, 130 mutations per individual per generation, then hardly any of these can be deleterious if the species is to survive.

This is one of the arguments in favor of Neutral Theory. Most mutations are neither deleterious nor beneficial. They are simply neutral with respect to natural selection.

Let's think about a typical protein-encoding gene.¹ The coding region is about 2,000 base pairs in length and consist of 666 codons. More than half these codons can be mutated to a new codon encoding a different amino acid without severe effects on the function of the protein.² These are called amino acid substitutions. Of the "essential" codons, many can tolerate mutations that create synonymous codons. Putting these facts together suggests that only about 20% of mutations to protein encoding regions are detrimental. The rest are effectively neutral.

This partially explains why we can tolerate 130 mutations per individual per generation. If only 20% were detrimental then the genetic load is reduced to about 26 mutations per generation.

That's still unacceptably high. It leads to the idea that a large percentage of our genome must be unaffected by mutations. In other words, genes represent only a small percentage of our genome and mutations can freely accumulate in the rest without detrimental consequences.

In order to bring the genetic load down to acceptable levels, the number of genes has to be less than 40,000 according to the arguments made in the 1960s. We now know that we have only 20,000 genes. Most of them encode proteins and the coding regions of those genes make up about 40,000,000 bp or about 1.3% of our genome [Junk in Your Genome: Protein-Encoding Genes].

Recall that only 20% of mutations in coding regions are likely to be detrimental. That means that the effective target size for detrimental mutations is about 20% x 1.3% = 0.26% of our genome. Out of 130 mutations, only 0.3 per individual per generation will be detrimental.³

Since we are diploid organisms, the 130 mutations in the zygote are spread out over two copies of our genome but almost all of them will be in the chromosomes coming from the father. Every zygote inherits one complete set of chromosomes with hardly any mutations while the other set has less than one detrimental mutation.

Because a large percentage of gene mutations are neutral, and because most of our genome is junk, we can easily tolerate 130 mutations per individual per generation without going extinct.

Creationists will never understand this because: (a) they believe that modern evolutionary theory is all about "Darwinism" and Darwinian evolution doesn't recognize neutral mutations and random genetic drift, and (b) they can't admit to junk DNA because that's the opposite of what intelligent design would look like.

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1. Similar arguments apply to genes that make functional RNAs and not proteins.

2. Over the course of several billion years of evolution it is unusual to see more than 30% sequence similarity between homologous genes. I realize that this is a somewhat circular argument but it's still a good one.

3. There are lots of other regions of the genome where mutations can be detrimental. I don't mean to imply that only protein encoding regions can be affected by mutations. Collectively, these other regions don't make up more than a few percent of our genome and they can tolerate many mutations [Genomes & Junk DNA]

Genetic Load

 
If the average rate of deleterious mutations is about 1 per individual per generation then the species can't survive. It means that most offspring will carry a mutation. This is an intolerable genetic load for a species.

In fact it's worse than that. Simple calculations suggest than even a rate of 0.1 deleterious mutations per individual will spell doom for the species. This is a well-known limitation and it was widely used in developing several key components of evolutionary theory and in explaining the size and composition of eukaryotic genomes.

The average total mutation rate in humans is about 130 mutations per genome per generation. Scordova concludes that this proves Intelligent Design Creationism [Nachman’s Paradox Defeats Darwinism and Dawkins’ Weasel]. It does no such thing. It proves once again that a little knowledge is a dangerous thing—especially in the mind of an IDiot.

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Monday's Molecule #144

 
This is another one of those times when there's no "molecule" that provides a clue to a Nobel Laureate.

Your task is to identify this creature and the reason why it's important. There are three Nobel Laureates who might be associated with the creature but two of them have already been covered. The last name of the this week's Nobel Laureate does not begin with the letters "E" or "D". Who is it?

The first person to identify the "molecule" and name the Nobel Laureate(s) wins a free lunch. Previous winners are ineligible for six weeks from the time they first won the prize.

There are seven ineligible candidates for this week's reward: Markus-Frederik Bohn of the Lehrstuhl für Biotechnik in Erlangen, Germany, Jason Oakley a biochemistry student at the University of Toronto, Dima Klenchin of the University of Wisconsin, Madison, Alex Ling of the University of Toronto, Bill Chaney of the University of Nebraska, Linda Zhang, a former student at the University of Toronto who will soon be on her way to graduate school at the University of Hong Kong and Kirill Zaslavsky, a Neuroscience student at the University of Toronto.

Dima, and Bill have agreed to donate their free lunch to an undergraduate. Consequently, I have two extra free lunches for deserving undergraduates. I'm going to award an additional prize to the first undergraduate student who can accept it. Please indicate in your email message whether you are an undergraduate and whether you can make it for lunch. If you can't make it for lunch then please consider donating it to someone who can in the next round.

THEME:

Nobel Laureates
Send your guess to Sandwalk (sandwalk (at) bioinfo.med.utoronto.ca) and I'll pick the first email message that correctly identifies the molecule(s) and names the Nobel Laureate(s). Note that I'm not going to repeat Nobel Prizes so you might want to check the list of previous Sandwalk postings by clicking on the link in the theme box.

Correct responses will be posted tomorrow.

Comments will be blocked for 24 hours. Comments are now open.

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The Hat Gene

 
Humans have always had a urge to cover their heads with various forms of headgear. There must be a hat gene in our genomes and it probably evolved in the human lineage after it split from chimpanzees. Chimps don't wear hats.

If you believe this then you've probably fallen for the idea that FOXP2 is a gene for language and that there's a gene for God/religion. See The hunt for the Hat Gene for a good discussion of where you're going wrong.

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Bill Maher on Vaccination

 
Bill Maher has attempted to clarify his position on vaccination [Vaccination: A Conversation Worth Having]. His blog is a lot like his TV show. It's a confusing, rambling, attempt at justifying an indefensible position using (attempted) humor, sarcasm and anecdote as a substitute for rationalism.

The question is whether vaccinations are good or bad. It's a strictly scientific question with a well-known scientific answer.

As far as I can tell, these are Bill Maher's main reasons for opposing vaccinations.

1. You wouldn't need to have vaccinations if you had a healthy immune system to begin with. (And I'm sure he has some opinions on what you should eat to ensure a healthy immune system.)


2. The success of vaccinations has been exaggerated by the medical community but he's not accusing anyone of a conspiracy.


3. Vaccines have bad things in them and they may be harmful to healthy people.


4. Vaccinations are supported by drug companies and you need to be skeptical about anything that's supported by large for-profit corporations.

I'm just trying to represent an under-reported medical point of view in this country, I'm not telling a specific pregnant lady what to do. With unlimited air time, I would have, for example, added to my discussion with Dr. Bill Frist on October 2 that, yes, any flu or health challenge can be dangerous when you're pregnant, and if your immune system is already compromised by, for example, eating a typical American diet, then a flu shot can make sense. But someone needs to be representing the point of view that says the preferred way to handle flus is to have a strong immune system to begin with, and getting lots of vaccines might not be the best way to accomplish that over the long haul.

Now, sometimes its OK to fuck with nature -- I believe "intelligent design" is often anything but intelligent; that "God's perfect universe" is actually full of fuck ups and design flaws, like cleft lips and Down Syndrome -- so correcting nature is sometimes the right thing to do. And then, sometimes its not. For me, the flu shot is in the "not" category.

In addition, my audience is bright, they wouldn't refuse a flu shot because they heard me talk about it, but if they looked into the subject a little more, how is that a bad thing? If they went to the CDC Web site and saw what's in the vaccine -- the formaldehyde, the insect repellent, the mercury -- shouldn't they at least get to have the information for themselves?

Instead of setting up this straw man of me not understanding germs or viruses, let's have a real debate about how much we should use vaccines and antibiotics. Of course it's good that we have them in our arsenal, but isn't the real skeptic the one who asks if these powerful but toxic methods do harm to what actually is a a very good defensive system, the one you were born with?

Also, I have never said there was a medical conspiracy. In fact, when Howard Dean asked me that, my response was "I wouldn't call it a conspiracy." Any more than there's a conspiracy for the Pentagon budget to be obscenely bloated and operated largely for the corporate welfare of defense contractors. If these are conspiracies, they're mostly legal ones that happen in plain sight. (Good time here to plug the hostess' book, Pigs At the Trough, it's all in there!) I have, in fact, used the phrase "medical-pharmaceutical-food industry" complex in comparing it to Eisenhower's famous depiction of a "military-industrial complex."

I believe in science and I believe in studies to determine the truth. I also believe Senator Ron Wyden of Oregon was correct when he said recently on MSNBC: "If you've got a checkbook in this town, you can get just about any set of facts you want." So if I remind you of a conspiracy theorist, you sometimes remind me of Britney Spears when she said "we should just do whatever the president says to do, and not ask questions and just support him." The medical community can be brutal on dissent, which would hold more weight if I thought this was a terribly healthy country, which it isn't. Health care is one sixth of our economy, and we spend way more on it than any other nation. The elephant in the room of the health care debate is that we are going to have a high health care bill every year no matter what law they pass because we're sick -- we need a lot of drugs and services.

Am I a conspiracy theorist if I suggest that since the network's nightly news broadcasts are sponsored almost entirely by prescription drug ads, that you might have to hold your breath a long time before you hear the alternative point of view to using pharmaceuticals to cure all our ailments?

Is it conspiracy theory to believe that American medicine too much treats symptoms and not root causes of disease? I always ask my friends when they go to the doctor for something, "Did your doctor ask you what you eat?" The answer is almost always 'no,' and a lot can be cured with diet and a healthier lifestyle. (And a lot can't. I also understand the role of genetics and generations of artificial selection). But Americans don't want to hear that, so doctors don't push it. It's easier and more profitable to write a prescription for Lipitor. They're not bad people, and at the end of the day, you can't make someone eat right. I like and respect all the M.D.s I've had over the years, and for the record, I have a naturopath doctor and I have a Western doctor. I would make an analogy to Republicans and Democrats: in both politics and health, I don't commit to either party because I'm on the side of the truth, whoever has it. In both cases, I'm an Independent.

This last quotation is the most revealing of all. Bill Maher listens to his naturopath doctor and feels competent to distinguish the truth when his quack doctor disagrees with evidence-based medicine (e.g. "Western" medicine).

In addition to falling for quackery, Bill Maher is making an elementary error in logic. Yes, it's true there are problems with modern medicine and the influence of drug companies, especially in the USA. But that's not to be confused with a rational discussion about the value of vaccinations. The scientific judgment about whether vaccinations are good or bad is independent of any opinions you might have about conspiracies, imagined or otherwise. The real question isn't about drug companies, it's whether you accept science or quackery.

The scientific evaluation of vaccination takes place in many countries throughout the world, including those with socialized medicine. They have all concluded that vaccinations are a proven technology that prevents disease.

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[Hat Tip and Thank-you to esaul]

timmyme

 
Ms Sandwalk just got an iPhone. She's thrilled by all the things it can do and I'm happy for her. However, most of the things an iPhone does are not important to me. I already have a camera and I'm not interested in iTunes. My Samsung flip phone works just fine, thank-you very much.

Up until last week, getting an iPhone was the last thing on my mind. It was a waste of money as far as I was concerned.

Then I learned about a wonderful app called timmyme [Tim Hortons coffee locator comes to the iPhone]. This little program allows you to find the nearest Tim Hortons no matter where you are in the civilized world.

I have to have an iPhone. To hell with the cost.

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Where do we come from? Where are we going?

 
This is the runner-up in Discover magazine's "Evolution in Two Minutes" contest. It was selected by PZ Myers [The Winner: Evolution in Two Minutes].

I seem to be one of the few people who think this is a horrible way to teach the public about evolution. I guess that's why I'm a curmudgeon.

I think we can do much better. I think we should do better.

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The Theory of Evolution

 
Here's one of the submissions to Discovery Magazine's "Evolution in Two Minutes" contest. It's the one chosen by viewers [The Winner: Evolution in Two Minutes].

I wish we could stop talking about "The" theory of evolution. There's really no such thing and the term conjurs up thoughts of evolution being only a theory. A better term is evolutionary theory.¹ A short description of modern evolutionary theory would include population genetics, the major mechanisms of evolution (natural selection and random genetic drift), and the latest theories of speciation. More sophisticated versions of evolutionary theory might include punctuated equilibria, lateral gene transfer, symbiosis, neutral theory, group selection, kin selection, species sorting and molecular phylogeny.

But before you can talk about any of these things you have to define evolution so that we all know what we're talking about. The consensus scientific definition of evolution—the fact, not the theory—is: "Evolution is a process that results in heritable changes in a population spread over many generations" or some related variation of that statement [What Is Evolution?].

The makers of these videos are free to select a definition that is not the consensus scientific definition but why would they do that? Is it a good idea to use another definition to teach the general public about evolution? What purpose does that serve?

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It's OK to talk about The theory of natural selection or The theory of punctuated equilbria.

Three Options

 
Here's a multiple choice question from Barry Arrington on Uncommon Descent [Is a Modern Myth of the Metals the Answer?].

He's concerned about the "fact" that "Darwinism" leads to immorality.

There are three and only three options.

1. We can continue to fill our children’s heads with standard Darwinian theory (which Dennett rightly calls “universal acid”), understanding that at least some of them are going to put two and two together and realize that the acid has eaten through all ethical principles – and act accordingly.

2. We can try to come up with a secular noble lie. “OK kids. You might have noticed that one of the implications of what I just taught you is that your lives are ultimately meaningless and all morals are arbitrary, but you must never act as if that is true because [fill in the noble lie of your choice, such as “morality is firmly grounded on societal norms or our ability to empathize with others”].

3. We can teach our children the truth – that the universe reveals a wondrous ordered complexity that can only be accounted for by the existence of a super-intelligence acting purposefully. And one of the implications of that conclusion is that God exists, and, reasoning further, He has established an objective system of morality that binds us all, and therefore the moral imperatives you feel so strongly are not just an epiphenomenon of the electro-chemical states of your brain.

Looking around I see that for the last several decades we have tried options one and two, and we have gotten what we have gotten. I vote to give option three a run.

Tough choice. I guess I'll opt for #2 although I don't think that telling children the truth about where morality comes from is a lie.

And correct me if I'm wrong, but haven't we already tried #3? It didn't work out very well, did it?

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Nobel Laureate: Johannes Fibiger

 

The Nobel Prize in Physiology or Medicine 1926

"for his discovery of the Spiroptera carcinoma"

Johannes Andreas Grib Fibiger (1867 - 1928) won the Nobel Prize for "proving" that gastric tumors could be caused by a nematode, Spiroptera carcinoma (now called Gongylonema neoplasticum). Unfortunately, later work showed that the nematode was not the cause of cancer, although it may contribute to a worsening of the symptoms.

This is one of the worst mistakes that the Nobel Prize committee has ever made in awarding a science prize. How did it happen?

Fiberger is rightly celebrated for his many important contributions to experimental medicine and for pioneering a modern version of clinical trials. When he learned of the work of Katsusaburo Yamagiwa, who induced cancer in rabbits by treating their skin with coal tar, he promoted Yamagiwa's results in Europe. Many people believe that Yamagiwa should have received the Nobel Prize.

Here is the entire Presentation Speech. The work sounds like something that deserves a Nobel Prize, doesn't it?
THEME:
Nobel Laureates

Your Majesty, Your Royal Highnesses, Ladies and Gentlemen.

Few diseases have the power of inspiring fear to the same degree as cancer. However, who would be surprised at that? How many times is this affliction not synonymous with a long, painful and grievous illness, how many times is it not equivalent to incurable suffering? It is therefore natural that we should strive to throw light upon its nature; but the road to this discovery is both long and difficult. Cancer always, in fact, presents the investigator with a number of obscure and unsolved problems. Thus the cause of cancer has for a long time baffled the penetrating studies of the most tireless research workers. Fibiger was the first of these to succeed in lifting with a sure hand a corner of the veil which hid from us the etiology of the disease; the first also, to enable us to replace with precise and demonstrable theories the hypotheses with which we had had to content ourselves.

For example, it had been thought for a long time that a causal connection existed between cancer and a prolonged irritation of some sort, mechanical, thermal, chemical, radiant, etc.; this supposition was supported by the incidence, sometimes verified, of cancer as an occupational disease. Cancer occurring in radiologists, chimney sweepers, workers in the manufacture of chemical products, establish so many examples of cancerous infection that one might believe they were provoked by radioactive or chemical irritation. However, each time experiment was resorted to in an attempt to provoke cancer in animals by irritants of this nature, it failed, and the animals refused to contract the disease.

Others, with all the more reason, sought to find in cancer the work of microparasites, for true neoplastic epizootics were thought sometimes to have been established in the animal world. But research into the pathogenic agent, the «cancer bacillus», and the experiments attempting to inoculate the disease had remained fruitless. Cancer has been equally attributed to other parasites, and notably to the worm. But, just as the attempts to provoke cancer, whether by inoculation or by irritation remained unproductive, in the same way it proved impossible to demonstrate experimentally that the disease was attributable to worms. These authorities who continued to support this thesis were, moreover, frequently considered to be fantasts. Because of the failure of attempts to establish, by experiment, the accuracy of any theory, there was no clear idea concerning the cause of cancer, and such in general was the position of this question. Then it was, in 1913, that Fibiger discovered that cancer could be produced experimentally.

It is of the greatest interest to follow Fibiger along the laborious path of his research. The first idea of his discovery, which was to make his name celebrated the world over came to him in 1907: he recorded in three mice in his laboratory (originating from Dorpat), a tumour, unknown until that time in the stomach; in the centre of the neoplasm he noted the presence of a worm belonging to the family of Spiroptera.

Fibiger did not succeed at first in proving a relationship existing between the formation of the neoplasm and the worm. The attempts to provoke a cancer in healthy mice by making them ingest neoplastic tissue from diseased mice, and containing worms or eggs, failed completely. Fibiger then had the idea that perhaps this worm, like many others, underwent part of its evolution from an egg to an adult individual in another animal, which served as an intermediate host. After numerous and vain attempts to find again mice attacked by the tumours seen in 1907 - he unsuccessfully examined more than 1000 animals - Fibiger eventually discovered in a sugar refinery in Copenhagen mice who exhibited in considerable numbers the type of tumour he was seeking; in these tumours he found once again the worm he had observed in 1907. The factory was at this time infested with cockroaches, and Fibiger was then able to establish that the worm in its evolution used these cockroaches as intermediate hosts. The cockroaches ingested the excreta of the mice, and with them the eggs of the worm. These developed in the alimentary tract of the cockroaches into larvae, which, like the trichina, were distributed into the muscles of the insects where they become encapsulated. The cockroaches were in their turn eaten by the mice and in the stomach the larvae transformed into the adult form.

By feeding healthy mice with cockroaches containing the larvae of the spiroptera, Fibiger succeeded in producing cancerous growths in the stomachs of a large number of animals. It was therefore possible, for the first time, to change by experiment normal cells into cells having all the terrible properties of cancer. It was thus shown authoritatively not that cancer is always caused by a worm, but that it can be provoked by an external stimulus. For this reason alone the discovery was of incalculable importance.

But Fibiger's discovery had a still greater significance. The possibility of experimentally producing cancer gave to the particular research into this illness an invaluable and badly needed method, lacking until this time, allowing the elucidation of some of the obscure points in the problem of cancer. Fibiger's discovery also gave remarkable impetus to research. Whereas research had, in many respects, entered upon a period of stagnation, Fibiger's discovery marked the beginning of a new era, of a new epoch in the history of cancer, to which the fruitful research made by him gave fresh vigour. From his discoveries we have continued to march forward and have gained valuable ideas as to the nature of this illness.

It is thus that Fibiger has been and will remain a pioneer in the difficult field of cancer research. «To my mind», says the famous English expert on cancer, Archibald Leitch, to name only one of the numerous critical commentators on Fibiger's research, «Fibiger's work has been the greatest contribution to experimental medicine in our generation. He has built into the growing structure of truth something outstanding, something immortal, quod non imber edax possit diruere.» It is for this immortal research work that Fibiger is today awarded the Nobel Prize for Medicine for 1926.

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The images of the Nobel Prize medals are registered trademarks of the Nobel Foundation (© The Nobel Foundation). They are used here, with permission, for educational purposes only.

Was Charles Darwin an Agnostic Atheist?

 
Let me say, right at the start, that I really don't care whether Charles Darwin was a deist, an agnostic, an atheist, or something else entirely. He died on April 19, 1882. That was a very long time ago. And the truth of evolution does not depend on what Darwin may or may not have believed about God.

Still, it's of some historical interest to learn what Darwin thought of religion. My own opinion is that these speculations are never going to be satisfactorily answered because Darwin was not always candid about his beliefs, for Emma's sake.

It may come as a bit of a surprise to find me favorably recommending an article on Uncommon Descent but this article by Flannery deserves your attention: Theist, Agnostic, Atheist: Will the Real Charles Darwin Please Stand Up?.

It's not going to make my agnostic friends happy but I think it's a pretty good analysis of Darwin's beliefs. I especially like the emphasis on the fact that his grandfather wasn't religious and his father (Robert) was an atheist. I'm pretty sure that his brother, Erasmus, was a nonbeliever as well. It strains credibility to imagine that Darwin was ever a religious man.

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November 11, 2009

 
Today is Remembrance Day in Canada. It's a day to remember that war is evil and horrible. It's a day to remember that war represents the ultimate failure of a civilization.

War is not glorious. People who kill other people are not heroes. The people they kill are not heroes. We are shamed when we turn average citizens into murderers. We lament their deaths because it means we have failed in our responsibility to maintain peace. They paid the price of our failure.

Soldiers are a necessary evil, like prison guards. The long range goal of a humane society is to eliminate armies (and prisons). Once a year, on this day, we need to think about how far we are from achieving that goal and what we can do to make it a reality.

We need to remember our past—the dirty, ugly, face of death and destruction—and resolve never to repeat it. We need to apologize to those men and women we forced to endure those horrors. We need to promise our children that we won't make them go to war.

No war is necessary. Tanks, bombers, and battleships are not necessary. I dream of an eleventh day of the eleventh month when, at the eleventh hour, no cannons are fired, no soldiers are marching, and no fighter planes are flying overhead. That will be a day to remember.

The greatest generation will be the one that avoids war. Perhaps our children's children will be that generation.

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[Photo: Dresden, February 14, 1945]

[Poster by Lorraine Schneider (1925-1972), for the Los Angeles organization Another Mother for Peace, 1967.]

The Positive Argument for Intelligent Design Creationism

 
I've often been critical of the arguments made by IDiots Intelligent Design Creationists. They consist mostly of claims that evolution can't happen.

It's only fair that I point you to a rebuttal of this point of view by none other than Casey Luskin [Misrepresenting the Definition of Intelligent Design].

Scott Minnich and Stephen Meyer also explain the positive argument for design:

Molecular machines display a key signature or hallmark of design, namely, irreducible complexity. In all irreducibly complex systems in which the cause of the system is known by experience or observation, intelligent design or engineering played a role the origin of the system … in any other context we would immediately recognize such systems as the product of very intelligent engineering. Although some may argue this is a merely an argument from ignorance, we regard it as an inference to the best explanation, given what we know about the powers of intelligent as opposed to strictly natural or material causes. (“Genetic analysis of coordinate flagellar and type III regulatory circuits in pathogenic Bacteria,” in Proceedings of the Second International Conference on Design & Nature, Rhodes Greece (2004).)

Let's see if I've got this right. We know about lots of irreducibly complex systems, such as the Krebs cycle and the bacterial flagella, that could easily have arisen by evolution. Nevertheless, according to the IDiots, we have to conclude that all such systems can only have been created by God.

That's what passes for a positive argument for Intelligent Design Creationism. I assume it's the best they've got.

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Monday's Molecule #143: Winner

 
The creature is a nematode, specifically a Soybean cyst nematode. The relevant Nobel Prize was to Johannes Fibiger who got for it "discovering" that the nematode Spiroptera carcinoma causes cancer. This species is now called Gongylonema neoplasticum and it doesn't cause cancer. Oops!

The first person to get it right was Linda Zhang, a former student at the University of Toronto who will soon be on her way to graduate school at the University of Hong Kong. The undergraduate winner is Kirill Zaslavsky, a Neuroscience student at the University of Toronto.

Many others got the right answer. It was easier than I thought it would be.

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Sometimes it's almost impossible to find an image of a specific molecule that honors a Nobel Laureate. This is another one of those times.

This spectacular photograph shows a particular kind of creature and its egg. You need to identify the phylum to which this species belongs and then use that as a clue to come up with an appropriate Nobel Laureate. Your answer should include the particular species that is associated with the Nobel Prize as well as the Nobel Laureate. Be careful, I want the modern name of the species—not the old name that was used when the Nobel Prize was announced.

Here's a clue. The Nobel Prize was awarded in the last century, not the current one. Here's another clue, outside of the Nobel Peace prize and the mini-Nobel Prize in Economics, this award is probably the biggest mistake that the prize committee has ever made.

The first person to identify the molecule and name the Nobel Laureate(s) wins a free lunch. Previous winners are ineligible for six weeks from the time they first won the prize.

There are six ineligible candidates for this week's reward: Joshua Johnson of Victoria University in Australia, Markus-Frederik Bohn of the Lehrstuhl für Biotechnik in Erlangen, Germany, Jason Oakley a biochemistry student at the University of Toronto, Dima Klenchin of the University of Wisconsin, Madison, Alex Ling of the University of Toronto, and Bill Chaney of the University of Nebraska.

Joshua, Dima, and Bill have all agreed to donate their free lunch to an undergraduate. Consequently, I have three extra free lunches for deserving undergraduates. I'm going to award an additional prize to the first undergraduate student who can accept it. Please indicate in your email message whether you are an undergraduate and whether you can make it for lunch. If you can't make it for lunch then please consider donating it to someone who can in the next round.

THEME:

Nobel Laureates
Send your guess to Sandwalk (sandwalk (at) bioinfo.med.utoronto.ca) and I'll pick the first email message that correctly identifies the molecule(s) and names the Nobel Laureate(s). Note that I'm not going to repeat Nobel Prizes so you might want to check the list of previous Sandwalk postings by clicking on the link in the theme box.

Correct responses will be posted tomorrow.

Comments will be blocked for 24 hours. Comments are now open.

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[Photo Credit: Wikipedia]

PZ Myers Gets It Wrong

 
Discover magazine sponsored a contest where you had to produce a two minute video explaining evolution. The judge was PZ Myers. Here's how PZ explains his choice [see The Winner: Evolution in Two Minutes].



Oh dear. Repeat after me, PZ, evolution is not natural selection!

This is, indeed, the 21st century, and not the Victorian England of Charles Darwin. We now know that evolution is any change in the frequency of alleles in a population. We know that for evolution to occur the change has to be genetic. We know that populations evolve, not individuals. We know that there are two main mechanisms of evolution: natural selection, and random genetic drift. It's a good idea to mention that variation within a species (population) arises from spontaneous mutations that create gene variants called alleles. That's what needs to be explained in two minutes.

Here's the winning video from Scott Hatfield, a high school biology teacher, and, more importantly, a blogger at Monkey Trials. Scott's a cool guy but it's not the video I would have chosen.

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