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In discussions of nature vs. nurture a common assumption is that if it is in the genes then we can’t fix it. Or we can only change it by eugenics or bioengineering babies. I wish to suggest a different approach.

The following links provide background:
Bioengineered Stem Cells Rejuvenate Muscles In Mice

Stem Cell Review Series: Aging of the skeletal muscle stem cell niche

Stem Cell Review Series: Regulating highly potent stem cells in aging: environmental influences on plasticity

Autism-spectrum disorder reversed in mice

Essentially all tissues turn-over with time. Some tissues such as the gut lining are replaced every three days, other tissues such as bone and fat are replaced over decades. (Proven by tracking green florescent cell markers over time.) In the adult brain, neurons are seldom replaced but new neurons are continually produced and some repair occurs. I believe it will eventually be shown that all tissues contain stem cells that have the potential to rebuild that tissue. Pluripotent hematopoietic stem cells from bone marrow can, with the proper differentiation signals, produce every cell type in the body. Stem cells make up less than 1/10,000 of the cells in tissue. (Adipose tissue may have a higher frequency of stem cells. Satellite cells in muscle tissue may also be relatively common. I welcome correction if I’m wrong about other tissue types.) If scientists could replace that small stem cell fraction and increase the rate of cell turn-over then eventually most of the body cells would become the new type.

Each day a few hundred stem cells in the bone marrow mobilize, circulate in the blood, and either migrate to specific tissue sites, resettle into other bone marrow niches, or die. (This has been observed in mice by florescent labeling of transplanted stem cells.) By injecting a few thousand stem cells each day, a person’s original bone marrow stem cells could be gradually replaced. The process would be accelerated if stem cell mobilizing drugs were used. Or if the old stem cells were selectively targeted for destruction.

By itself, transplants using young stem cells don’t significantly repair damage or rejuvenate tissue. Proper signals are needed to mobilize the stem cells to the desired site, to cause the stem cells to divide, to cause the stem cells to differentiate into the right cells, and to cause those cells to integrate into the existing tissue. This is what happens when our body successfully heals a wound. For rejuvenation scientists also need to kill senescent cells and remodel the extracellular matrix. This isn’t easy but significant progress is being made.

Imagine that in ten years the technology existed to completely replace the stem cells in one mouse with stem cells from a different mouse. And that the tissue turn-over rate was increased so that most of the mouse body cells derived from the second mouse. How much remodeling of body and brain would occur? Some body structures would have been largely fixed during development but much would change due to the new cell DNA. Potentially, a sick or dull mouse could be made healthy or smart by such a full body stem cell makeover.

In addition there will be progress in restructuring damaged parts of the brain. This may require putting the tissues back in an earlier developmental state so as to rebuild a functional structure, e.g., regrow a nerve fiber connection. Memories stored in the original brain tissue structure would be lost but functionality would be regained after training. Even developmentally fixed traits might be altered by selective rebuilding of body structures.

The stem cell donors might be world class athletes, handsome, musically gifted, with IQ’s over 160. By expanding a cell line in culture, one donor could supply an unlimited number of recipients. Modest genetic engineering might improve the cell line. Even the germ cells would be replaced so future offspring would not be genetically related to the original person.

Would you choose to undergo such a metamorphosis? Externally you might change in just a couple of years. Your parents and friends might not recognize you. Internally you should have pretty much the same memories. However, your internal processing might be different and your personality might change. I think you would feel like the same person but you would also know that you were different. Like remembering how it felt to be depressed…you were you then and you are you now but you aren’t the same you. Hopefully your spouse would like the new you. This would be a little like massive cosmetic surgery.

This is a potential solution to the unfair distribution of good genetic traits. It could be a win-win for all groups. Defeat old age, class divisions, and racial strife in one stroke. I would do it to myself and would support having the government offer free treatment to everyone. It might even be offered as an alternative to execution or long term imprisonment.

• Category: Science • Tags: Life Hacking 
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‘Smart’ mice teach scientists about learning process, brain disorders

Mice genetically engineered to lack a single enzyme in their brains are more adept at learning than their normal cousins, and are quicker to figure out that their environment has changed, a team led by researchers at UT Southwestern Medical Center has found.

The group is also beginning a search for drugs that might create the same effects without genetic manipulation and monitoring the animals’ health and behavior over time.

The key in this study was being able to “knock out” the gene for Cdk5 only in the brain, and only when the mice were adults. This technique, only recently developed and called conditional knockout, allows much more sophisticated experiments than traditional knockout, which entirely eliminates the gene.

Normally, Cdk5 works with another enzyme to break up a molecule called NR2B, which is found in nerve-cell membranes and stimulates the cell to fire when a nerve cell signaling molecule, or neurotransmitter, binds to it. NR2B previously has been implicated in the early stages of learning.

The new research showed that when Cdk5 is removed from the brain, the levels of NR2B significantly increase, and the mice are primed to learn, Dr. Bibb said.

Evolved biological systems aren’t optimal…just good enough. Knowing how the system works should lead to interventions that improve function. In the coming decades there should be nutritional, drug, training, genetic, and cybernetic enhancement of brain function.

• Category: Science • Tags: Brain 
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Engineering Bacteria to Harvest Light

Some bacteria, such as cyanobacteria, use photosynthesis to make sugars, just as plants do. But others have a newly discovered ability to harvest light through a different mechanism: using light-activated proteins known as proteorhodopsins, which are similar to proteins found in our retinas. When the protein is bound to a light-sensitive molecule called retinal and hit with light, it pumps positively charged protons across the cell membrane. That creates an electrical gradient that acts as a source of energy, much like the voltage, or electromotive force, supplied by batteries.

First discovered in marine organisms in 2000, scientists recently found that the genes for the proteorhodopsin system – essentially a genetic module that includes the genes that code for both the protein and the enzymes required to produce retinal – are frequently swapped among different microorganisms in the ocean.

Intrigued by the prospect that a single piece of DNA is really all an organism needs to harvest energy from light, the researchers inserted it into E. coli. They found that the microorganisms synthesized all the necessary components and assembled them in the cell membrane, using the system to generate energy.

The findings have implications for both marine ecology and for synthetic biology, an emerging field that aims to design and build new life forms that can perform useful functions. Giant genomic studies of the ocean have found that the rhodopsin system is surprisingly widespread. The fact that a single gene transfer can result in an entirely new functionality helps explain how this genetic module traveled so widely. In fact for microbes, this kind of module swapping may be the rule rather than the exception.

• Category: Science • Tags: Genetic Engineering 
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Genetic studies endow mice with new color vision

Although mice, like most mammals, typically view the world with a limited color palette – similar to what some people with red-green color blindness see – scientists have now transformed their vision by introducing a single human gene into a mouse chromosome. The human gene codes for a light sensor that mice do not normally possess, and its insertion allowed the mice to distinguish colors as never before.

In a study published in the March 23, 2007, issue of the journal Science, Howard Hughes Medical Institute researchers at Johns Hopkins, together with researchers at the University of California at Santa Barbara, demonstrated in a series of cleverly designed color vision tests that the genetic modification allows mice to see and distinguish among a broader spectrum of light waves. The experiments were designed to determine whether the brains of the genetically altered mice could efficiently process sensory information from the new photoreceptors in their eyes. Among mammals, this more complex type of color vision has only been observed in primates, and therefore the brains of mice did not need to evolve to make these discriminations.

The new abilities of the genetically engineered mice indicate that the mammalian brain possesses a flexibility that permits a nearly instantaneous upgrade in the complexity of color vision, say the study’s senior authors, Gerald Jacobs and Jeremy Nathans.

“Our observation that the mouse brain can use this information to make spectral discriminations implies that alterations in receptor genes might be of immediate selective value not only because they expand the range or types of stimuli that can be detected but also because they permit a plastic nervous system to discriminate between new and existing stimuli,” the authors wrote in the Science paper. “Additional genetic changes that refine the downstream neural circuitry to more efficiently extract sensory information could then follow over many generations.”

I’m surprised that the mouse brain visual system is sufficiently plastic that the altered mice gained significant color differentiation ability.

Update: Carl Zimmer on Mouse Color Vision

• Category: Science 
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Sleep Disorders Can Impair Children’s IQs As Much As Lead Exposure

UVa researchers have been studying sleep disturbances in children with enlarged tonsils and adenoids for the past seven years. In a recent study, they discovered that youngsters who snore nightly scored significantly lower on vocabulary tests than those who snore less often.

According to Dr. Suratt, the vocabulary differences associated with nightly snoring are equivalent to the IQ dissimilarities attributed to lead exposure. “Studies show that, even at nontoxic levels, lead exposure can reduce a child’s IQ by more than seven points,” he notes.

In a series of studies involving six to twelve-year-olds, researchers have been piecing together a list of risk indicators. So far, snoring frequency combined with sleep lab results have proven to be the most reliable predictors of intellectual impairment and behavioral problems. Sleep duration and race appear to be important risk factors, too.

This study only shows correlation but when combined with research showing the importance of sleep for consolidating memories the story becomes interesting. Perhaps treatments that improve sleep quality will increase IQ?

• Category: Science • Tags: IQ 
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CHRM2 Gene Variants Associated with Intelligence

“Some of the participants in the study also took the Wechsler Adult
Intelligence Scale-Revised, a traditional IQ test. In all, members of 200
families, including more than 2,150 individuals, took the Wechsler test, and those results were matched to differences in individuals’ DNA.

By comparing individual differences embedded in DNA, the team zeroed in on CHRM2, the neuronal receptor gene on chromosome 7. The CHRM2 gene activates multitude of signaling pathways in the brain involved in learning, memory and other higher brain functions. The research team doesn’t yet understand how the gene exerts its effects on intelligence.”

Dick’s team is not the first to notice a link between intelligence and the CHRM2 gene. In 2003, a group in Minnesota looked at a single marker in the gene and noted that the variation was related to an increase in IQ. A more recent Dutch study looked at three regions of DNA along the gene and also noticed influences on intelligence. In this new study, however, researchers tested multiple genetic markers throughout the gene.

“If we look at a single marker, a DNA variation might influence IQ scores between two and four points, depending on which variant a person carries,” Dick explains. “We did that all up and down the gene and found that the variations had cumulative effects, so that if one person had all of the ‘good’ variations and another all of the ‘bad’ variations, the difference in IQ might be 15 to 20 points. Unfortunately, the numbers of people at those extremes were so small that the finding isn’t statistically significant, but the point is we saw fairly substantial differences in our sample when we combined information across multiple regions of the gene.”

Dick says the next step is to look at the gene and its numerous variants to learn what is going on biologically that might affect cognitive performance. Presently, she says it’s too early to predict how small changes in the gene might be influencing communication in the brain to affect intelligence, and she says it’s nearly certain CHRM2 is not the only gene involved.

Prior GNXP references to CHRM2:

Thompson and Gray: Neuroscience, genes, and IQ

More red meat

• Category: Science • Tags: General Intelligence, Genetics 
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“What we found was that, in certain cases, edited versions of these microRNAs are being produced that differ from the unedited versions by only a single nucleotide change,” says Kazuko Nishikura, Ph.D., a professor in the Gene Expression and Regulation Program at Wistar and senior author on the study.

“These edited microRNAs are not encoded in the DNA, which means that at least two versions can being produced by one gene. This was not anticipated – it was something really new.

Looking more closely, we realized that the substitution we’d identified occurred in a particularly critical region of the molecule, the first 7 or 8 nucleotides – out of a total of only 19 or 21 – that define the molecule’s target specificity. This suggested that the change might well redirect these edited microRNAs to silence entirely different sets of genes from the unedited versions.”

• Category: Science • Tags: Genetics 
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DNA no-no’s

Elements can be detected in the solar energy spectrum because elements absorb specific wavelengths creating dark lines in the hot body radiation spectrum. By analogy “forbidden” DNA sequences would form “dark lines” in the expected DNA sequence frequency spectrum. Find interesting stuff by what is missing. Neat.

“COULD there be forbidden sequences in the genome – ones so harmful that they are not compatible with life? One group of researchers thinks so. Unlike most genome sequencing projects which set out to search for genes that are conserved within and between species, their goal is to identify ‘primes’: DNA sequences and chains of amino acids so dangerous to life that they do not exist.”

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Productive Nanosystems

First molecular biology and now nanotechnology.

• Category: Science 
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Cellular Visions: The Inner Life of a Cell

This animation demo shows how biology may be taught in the near future.


“In some instances, that meant sacrificing literal accuracy for visual effect. What we did in some cases, with the full support of the Harvard team, was subtly change the way things work,” Liebler says. “The reality is that all that stuff that’s going on in each cell is so tightly packed together that if we were to put every detail into every shot, you wouldn’t be able to see the forest for the trees or know what you were even looking at. One of the most common things we did, then, was to strip it apart and add space where there isn’t really that much space.”

There isn’t a soundtrack to explain what you are seeing and the animation sequences jump too much for teaching. However, if you know some microbiology you can recognize much of what is being shown.

• Category: Science 
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Human bodies maintain an optimal environment for cellular function. Cold-blooded animals function sluggishly when cold. I’ve wondered how bacteria manage to function at different temperatures. I’d assumed that bacteria are highly adapted to either high or low temperatures and that homeostatic feedback maintains biological systems in a viable range over modest daily temperature changes. But what happens when their environment rapidly changes? Does that bacterial line die out? Perhaps not.

Bacteria beat the heat

“A general rule for enzyme reactions states that as the heat rises, so does the reaction rate. Contrary to this rule, and the scientist’s expectations, both reaction rates peaked at a certain point, and remained steady thereafter. For each enzyme, the peak occurred in the bacteria’s ‘comfort zone.’ Further comparisons of the enzymes, which were nearly identical, turned up differences in just two of the hundreds of amino acids making up the enzyme sequence. When the scientists replaced these two amino acids in the enzyme adapted to the moderate temperatures with those of the heat-loving enzyme, they observed an increase of about 10 degrees in the average temperature at which the reaction rate peaked. Scherz: ‘This study shows that enzyme efficiency is tuned to the average temperature of the bacterial habitat, rather than the immediate conditions. This may protect the cells from harmful swings in enzyme activity’ “

In this experiment, changing two amino acids in an enzyme changed the temperature of peak reaction rate. The bacteria colony could adapt to new temperatures with just a few mutations. Life has evolved to adapt rapidly to changing environments. Lifeforms that couldn’t adapt went extinct.

• Category: Science 
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This article relates to the nature of belief. When science explanations are beyond the comprehension of intelligent adults, science becomes unsatisfying dogma.

“In my own field of complex systems theory, Stephen Wolfram has emphasized that there are simple computer programs, known as cellular automata, whose dynamics can be so inscrutable that there’s no way to predict how they’ll behave; the best you can do is simulate them on the computer, sit back, and watch how they unfold. Observation replaces insight. Mathematics becomes a spectator sport.

If this is happening in mathematics, the supposed pinnacle of human reasoning, it seems likely to afflict us in science too, first in physics and later in biology and the social sciences (where we’re not even sure what’s true, let alone why).

When the End of Insight comes, the nature of explanation in science will change forever. We’ll be stuck in an age of authoritarianism, except it’ll no longer be coming from politics or religious dogma, but from science itself.”

In the near future Google will determine what we “know” or “believe”. Asking the Internet will be as easy as asking our own memory and the answers will be more reliable. We won’t “know” why; we will only know that the Google answers are right. Google will be the modern oracle.

Perhaps we can avoid this fate by expanding human intelligence and consciousness. Or perhaps a complex universe just won’t fit into a human brain.

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“In a surprise about E. coli that may offer clues about how human cells operate, the PNAS paper reports that only a handful of dominant metabolic states are found in E. coli when it is “grown” in 15,580 different environments in computer simulations.”

“When it comes to genomes, a great deal of complexity boils down to just a few simple themes,” said Bernhard Palsson, a professor of bioengineering at UCSD’s Jacobs School of Engineering and co-author of the study, which was made available online Dec. 15. “Researchers have confirmed the complexity of individual parts of biochemical networks in E. coli and other model organisms, but our large-scale reconstruction of regulatory and metabolic networks involving hundreds of these parts has shown that all this genetic complexity yields surprisingly few physiological functions. This is possibly a general principal in many, if not all, species.”

Similar principals have broad application.

1) Thousands of elements interacting in nonlinear dynamic feedback systems.
2) Evolutionary competition with survival of the fittest.
3) Subsets of elements operating together to maintain a specific state. Optimized to support that state.
4) States associated with successful survival strategies.

Applications in low-level neural circuits, high-level thought patterns, knowledge domains, belief systems, and social organizations.

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UCLA scientists use statins to overcome learning disabilities in mice

“In a surprise twist that recalls the film classic “Flowers for Algernon,” but adds a happy ending, UCLA scientists used statins, a popular class of cholesterol drugs, to reverse the attention deficits linked to the leading genetic cause of learning disabilities. The Nov. 8 issue of Current Biology reports the findings, which were studied in mice bred to develop the disease, called neurofibromatosis 1 (NF1).

The results proved so hopeful, that the Food and Drug Administration approved the use of the drugs in three clinical trials currently under review to test the effect of statins in children and adults born with NF1. The findings could help the estimated 35 million Americans who struggle with learning disabilities.”

“This is mind-blowing – we think we have a real fundamental reason to be optimistic,” explained Silva. “Here is a drug that affects a key learning and memory pathway, and completely rescues the most common genetic cause for learning disabilities. We don’t have to do extensive clinical trials for toxicity or safety – these were already completed for other uses.”

“NF1 afflicts one in 4,000 people, about one million people worldwide.”

I don’t know where they get the estimate of possibly helping 35 million Americans, but even if it ONLY helps one million people, it is good news.

• Category: Science 
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From “The Genius” blog. (From a link by Jason Malloy.)

“If you have academic access to Nature magazine you should totally check out this awesome movie thing about RNA interference and silencing. Watching stuff like this, I think, gives you good little models to play with in your head when you are trying to think about this stuff. From now on, when I think of Dicer, it will do that cool spinny thing to chop up the dsRNAs.”

I don’t have academic access to Nature but the link worked fine for me. Definitely worth a look.

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Scientists Crack Code for Motor Neuron Wiring

“Dasen’s functional analysis revealed a Hox coding hierarchy. “He found that the Hox proteins involved in pool identity are different from those involved in column identity,” said Jessell. “So from these data, the idea began to emerge that within the chromosomal Hox clusters, some Hox proteins are dedicated to broad aspects of motor neuron differentiation, and others to finer aspects of diversification. Ultimately, what crystallized from these experiments was a code — an organized relationship between Hox proteins, their chromosomal organization, and the differentiation and connectivity of motor neuron pools,” he said.

Jessell said this code appears to govern three levels of motor neuron organization: the columnar organization that ensures that motor neurons project into the limb; the divisional organization of motor neurons that determines whether motor neurons project to muscles in the dorsal or ventral halves of the limb; and finally, the motor neuron pool identity that governs the muscle target of each set of motor neurons. In a key set of experiments, Dasen showed that alterations in Hox expression patterns in specific neurons resulted in changes in motor neuron identity, and in their connectivity to muscle targets.”
“The studies also raise the possibility that the combinatorial code contains additional information, beyond the regulation of motor neuron wiring. “This is still conjecture, but the sheer number of Hox proteins, and their capacity to direct neuronal differentiation, suggests that they may also impart identity to the interneurons that enable them to connect selectively with motor neurons. And, aspects of the code could also give identity to sensory neurons, enabling their connections with motor neurons,” said Jessell. Deciphering the entire Hox code could provide crucial insights into the organization of the complex circuitry that the spinal cord uses to control muscle action.”

(Warning: leaving the realm of science and entering Fly speculations…or fantasy. Erroneous info ahead.)

We have two pieces of the puzzle. The Hox proteins provide a label (or trigger) that tells a cell what it is. We also have gene chips and protein chips that can tell us what genes are turned-on and what proteins are being built. So what occurs in between?

I believe there is DNA whose expression is triggered by the Hox proteins and that DNA controls the cell specific gene expression. I think of this DNA as scripting code. The scripting DNA wouldn’t directly code for the common structural, enzymatic, or signaling proteins.

The scripting DNA would be short in comparison to most protein-coding DNA. A mutation in this DNA would only affect specific cell types so evolution of the scripting DNA could lead to optimal gene expression for different tissues. (Whereas a mutation in most protein-coding genes would affect many cell types.) Since the scripting DNA would be short, mutations would be infrequent so less selection would be needed to maintain genome quality. Scripts would be built on top of other scripts. Low-level common scripts should be highly conserved.

The scripting DNA should have a distinctive nucleotide signature. Unlike protein-coding DNA, every nucleotide could be significant. The script DNA would be copied into RNA that would then fold into specific functional shapes. So the RNA functional shape patterns should be represented in the DNA sequence patterns. (Some scripting DNA could act through regulatory proteins. My guess is that nature doesn’t care if “machine code”, “C code”, or “scripting code” is mixed together into a complex jumble.)

My guess is that most of the design information for an animal is in this scripting DNA. Protein-coding genes tell how to build blocks and scripting DNA tells how to put the blocks together to form an animal.

What would be scripted?

Consider brain wiring. How is one neural cluster connected to another by a nerve bundle? First each cluster of neurons must travel to the proper location in the brain. The body has many fluid pathways. There is the blood circulatory system, the lymph system, and slow fluid flow from the blood system through the tissues to the lymph system. (In the earliest embryonic stages, diffusion would play a major role. As the embryo grows I’d expect fluid flow to become more important.) Thus the entire body is a drainage system with directional fluid flow. These fluid flows serve to pass chemical signals from one place to another. So chemical gradients could be used to guide cells to their destination. Each neuron type would need its own address (Hox proteins?) and instructions that convert that address into directional movements (DNA scripts?).

Once in place, the neuron sends out chemical signals. Somehow two neural clusters recognize specific signals and axons grow to connect the regions. Some of the guiding is constrained by body architecture. The axons are going to flow along the body fluid paths carrying the proper chemical signal. But occasionally the axon is going to have go against the main fluid flow and follow the chemical gradient generated by the target neurons. So DNA has code for the target neurons releasing specific signals and for the source neuron axons to respond to those signals and grow toward those targets.

There may be many unique chemical messengers and many unique receptors. (Protein-coding genes with alternate splicing could generate the unique types. A DNA script could be translated into RNA that interacts with intron RNA to control mRNA splicing.) Or there might be many ways for a cell to interpret chemical signals. Suppose a neuron axon is tracking three chemical signals. The neuron might track signals with a special ratio of those three types. A DNA script that controlled the ratio of cell membrane receptors for those signals might determine what signals caused the largest response. Or perhaps a neuron recognizes a time varying pattern of chemical messengers. There are many ways that signals can be sent and recognized. All of the ways require DNA information.

Clearly the wiring isn’t determined down to the individual neurons. But there are many nerves and many specialized brain modules. Thus the information needed to wire the human body must be extensive.

Also consider instinctive behavior. Every instinct is embedded in neural structures. So there must be DNA that codes for specific neural patterns that underlie specific instincts. So even more information is needed to build that brain.

Why do I think that scripting DNA exists?

I don’t believe there is enough information in the protein-coding DNA to build a human being. There is twice as much non-coding DNA conserved in the genome as there is protein-coding DNA. Since the scripting DNA would tend to be shorter than the protein-coding DNA it could hold much more design information. Scripts could be built based on top of lower-level scripts making the information storage more efficient. Our cells contain elaborate molecular machinery for manipulating DNA and RNA. So there are many mechanisms by which DNA/RNA might regulate gene expression or protein production without requiring a protein intermediary.

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Based on Body Size, Bacteria and Elephants Have Similar Metabolism, Ecologists FindUCR-led research team shows that organisms use their biochemical characteristics to overcome limitations arising from their body size

“The researchers’ analysis also shows that the rate of energy consumption per unit body mass declines with growing body size in groups of evolutionarily close organisms, such as mammals. For example, one gram of an elephant’s body uses up 25 times less energy than does one gram of a shrew’s body, accounting for why shrews have to eat more often than elephants. On the other hand, a bacterium, which is not closely related to an elephant in an evolutionary sense, consumes approximately the same energy per unit body mass as the elephant.”

This interests me because it is an attempt to discover meta-knowledge that applies to a much larger set of detailed knowledge in specific domains. I believe such re-organization of information is necessary if there is to be any hope for a human to comprehend even a small fraction of the world’s knowledge. The world has so many stories that a person can only learn a few of the most powerful.Clearly such meta-knowledge has limits. That paragraph could be re-stated to say a shrew burns 25 times as much energy as a bacterium. So the meta-knowledge both captures important information and misses important information.

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(Jason Malloy provided this interesting link in the GNXP Forum)

Smarter on Drugs

“Just as Ritalin can improve the academic performance of hyperactive children, it can do the same for normal children. It is commonly thought to boost SAT scores by more than 100 points, for both the hyperactive and the normal user. Many healthy young people now use it that way for that purpose, and quite frankly, there is no stopping this abuse.”

I found this claim interesting. I don’t have the background or knowledge to evaluate it. Hopefully knowledgeable readers will comment.

Up to 5% of males are diagnosed as having ADHD. Many schools require medication for kids diagnosed as having ADHD. Wouldn’t a 100-point boost in SAT scores show up in national test scores? Is there any study that backs up the author’s claim?

Note that 100 SAT points is equivalent to about 7 IQ points. But even if the 100-point claim is valid that doesn’t mean that Ritalin is increasing IQ. E.g., vocabulary test correlate highly with IQ tests. But having access to an online dictionary that significantly improved one’s performance on a vocabulary test wouldn’t increase a person’s IQ. It would just break the connection between tested vocabulary and IQ. Likewise Ritalin might increase the ability to focus and so increase test performance but that increased performance might not reflect increased “g”.

(Many abilities correlate with “g”. As biotech improves so that specific abilities can be enhanced, it is not clear to me that “g” is being increased. The science of measuring “g” will have to adapt to advancing brain tech.)

This article says that under long-term treatment with Ritalin, ADHD children showed a 2.5 point increase in total IQ. Other articles claim there is no improvement in IQ (In fact some articles claim that if used too early, Ritalin can hinder proper brain development.)

(I would like an online resource that numerically documented the mental effects of substances such as caffeine and Ritalin.)

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“unscripted biochemical variations, or noise, combined with time delays in certain biochemical reactions may lead to oscillations in gene regulation that couldn’t otherwise be predicted. Such noise is routinely described by cell biologists who record large phenotypic differences between supposedly identical cells in a single flask of growth medium.”
“The fine-grain fluctuations we see in the genetic regulation within single cells may lead to new insights about variability at the level of the whole organism”

Noise is under appreciated. Some speculation on noise…

Noise prevents sharp “edge” effects. Imagine a thermostat with no “noise”. Too cold then turn on, too hot then turn off, the heater would be continually turning on and off. Slop in a steering wheel is another example. If the wheel is too responsive then the driver over corrects.

“Noise” in the genome: Mutations generate new gene alleles. If the new allele significantly improves fitness then it rapidly increases in frequency. If the new allele significantly decreases fitness, then it may disappear. But many mutations won’t have much of an effect either way. Such gene alleles act as genetic “noise”. Such genetic noise produces statistical “outliers” that are extreme phenotypes. (E.g., very high IQ.)

Gene allele “outliers” provide feedback. If the environment changes so that the “outlier” significantly improves fitness then that gene allele frequency increases and the population rapidly adapts. Negative “outliers” would “push” the population away from the “bad” allele. Thus noise makes the genome more robust and stable.

Molecular noise provides the random generator needed to for our body’s immune system to build broad coverage against potential invaders and generate new antibodies to specific molecular targets against invaders that make it past the first immune barrier.

Noise can provide the “mutations” in a Darwinian mechanism such as might occur in thinking and skill learning. (Similar to “heat” in simulated annealing.)

Noise keeps certain neuronal systems healthy. Too little noise can lead to heart attacks or seizures.

Update from Razib: Look in the gnxp files for “noise,” that is the PDF of the paper that the article is based on.

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If prediction of anti-social behavior becomes sufficiently accurate, will society adjust by mandating treatment, monitoring, or incarceration BEFORE a crime has been committed? If a person’s behavior is largely a result of an innate, abnormal brain structure, is he morally responsible for his actions. How would our legal and moral systems adapt?

First evidence of brain abnormalities found in pathological liars

MRI brain scan the ultimate lie detector

Perhaps psychopaths could be reliably detected by observing brain function while showing images that normally evoke emotional responses. Perhaps potential child molesters could be identified based on brain responses to images of children. Or potential terrorists.

• Category: Science 
The “war hero” candidate buried information about POWs left behind in Vietnam.
Are elite university admissions based on meritocracy and diversity as claimed?
The sources of America’s immigration problems—and a possible solution