Switching on humanity

Humans, chimps, and bonobos share a little over 99% of their DNA.

That remaining just-under-one-percent accounts for every physical difference between you and our nearest ape relatives.  It's natural enough to be surprised by this; we look and act pretty different from them most of the time.  (Although if you've read Desmond Morris's classic study The Naked Ape, you'll find there's a lot more overlap between humans and apes behaviorally than you might have realized.)

[Image licensed under the Creative Commons Greg Hume, Bonobo-04, CC BY-SA 3.0]

Part of that sense of differentness is from the cultural context most of us grew up in -- that "human" and "animal" are two separate categories.  In a lot of places that comes from religion, specifically the idea that the Creator fashioned humans separately from the rest of the species on Earth, and that separation persists in our worldviews even for many of us who no longer believe in a supreme deity.  The truth is we're just another branch of Kingdom Animalia, Phylum Chordata, Class Mammalia, Order Primata, albeit a good bit more intelligent and technologically capable than most of the other branches.

It's that last bit that has captured the curiosity of evolutionary geneticists for decades.  The similarities between ourselves and apes are obvious; but where did the differences come from?  How could less than one percent of our DNA be responsible for all the things that do set us apart -- our larger brains, capacity for language, upright posture, and so on?

Just last week, a paper in the journal Cell, written by a team out of Duke University, may have provided us with some answers.

The researchers found that the most striking differences between the genomes of humans and those of chimps and bonobos lay in a set of switches they dubbed Human Ancestor Quickly-Evolved Regions (HAQERs -- pronounced, as you might have guessed, like "hackers").  HAQERs are genetic regulatory switches, that control when and how long other genes are active.  The HAQER sequences the team discovered seem to mostly affect two sets of developmental genes -- the ones that influence brain complexity and the ones involved in the production of the gastrointestinal tract.

"We see lots of regulatory elements that are turning on in these tissues," said Craig Lowe, who co-authored the paper, in an interview with Science Daily.  "These are the tissues where humans are refining which genes are expressed and at what level...  Today, our brains are larger than other apes, and our guts are shorter.  People have hypothesized that those two are even linked, because they are two really expensive metabolic tissues to have around.  I think what we're seeing is that there wasn't really one mutation that gave you a large brain and one mutation that really struck the gut, it was probably many of these small changes over time."

What's most interesting of all is that the HAQER sequences provide another example of how evolution is so frequently a trade-off.  Consider, for example, our upright posture; our vertebral column evolved in animals that walked on all fours, and when we switched to being bipedal it gave us the advantage of freeing up our hands and being able to see farther, but it bequeathed a legacy of lower back problems most other mammals never have to worry about.  Here, the HAQERs that seem to be responsible for our larger and more complex brains also correlate to a variety of disorder susceptibilities.  Particular variants of HAQER sequences are associated with a higher risk of hypertension, neuroblastoma, depression, bipolar disorder, and schizophrenia.

It's just the way genetic change works.  Sometimes you can't improve one thing without screwing something else up.  And if, on balance, the change improves survival and reproductive likelihood, it's still selected for despite the disadvantages.

So we seem to finally be making some inroads into the question of why such a tiny slice of our genome creates all the differences between ourselves and our nearest relatives.  It's worth a reminder, though, that we aren't substantially different than the other species we share the planet it.  It reminds me of the famous quote from Chief Seattle: "We did not weave the web of life, we are merely one strand in it.  Whatever we do to the web, we do to ourselves."

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The scent of memory

There are two very specific scents that will always remind me of my beloved grandma, with whom I lived for a year and a half when I was eight or nine years old.

One is the flowers of the sweet olive tree.  Sweet olive is a small tree with glossy leaves and little, cream-colored flowers with a fruity, spicy smell a little reminiscent of a combination of fresh peaches and vanilla.  My grandma had a beautiful sweet olive, and when it flowered in early summer, it perfumed the entire yard.

The other is the smell of old books.  When I lived with my grandma my bedroom was in the attic, a maze-like twist of rooms and alcoves with sloped ceilings, a wooden floor, and shelves laden with what seemed to my young eyes like thousands of books.  That dusty, dry smell when you turn the cover of a book that hasn't been opened in decades immediately brings me back to that happy time that was, in a lot of ways, like an oasis of calm and happiness in an otherwise troubled and turbulent childhood.

[Image licensed under the Creative Commons Lin Kristensen from New Jersey, USA, Timeless Books, CC BY 2.0]

I suspect a lot of you can relate to my experience of having scents trigger memories, but it's hardly a new observation.  This phenomenon was the impetus for Marcel Proust's Remembrance of Things Past, in which the entire book begins with the protagonist having a memory triggered by the smell and taste of madeleine cake and tea.  What's been less obvious is why smell has such a strong link to memory -- for many people, stronger than any of the other senses.

Two recent papers, one in the journal Cell and the other in Nature, have elucidated why that might be.  One reason is that the sense of smell is so specific -- we have over four hundred different types of olfactory sensors, each responsive to different molecules, and those sensors are connected through the olfactory bulb of the brain directly to the hippocampus (a major memory center) and the parts of the cerebral cortex involved in storage of memories.

There's a lot we still don't understand, however.  In part, our responsiveness to scents seems to have an epigenetic component -- the phenomenon wherein traits can be inheritable without involving alterations in the DNA.  For example, the grandchildren of mice who were given mild electric shocks when exposed to the scent of cherry blossoms have an aversive reaction to the odor even though they were never shocked themselves.  (This may sound like a Lamarckian "inheritance of acquired characteristics" model, and in a way, it is; but epigenetic effects usually happen because the trait involved hormonal alteration of the rate of gene expression, which can affect the children -- and grandchildren -- without the actual DNA being changed.)

What it immediately made me wonder is how this affects the experience of animals with way more sensitive noses -- like dogs.  Dogs' big snouts have fifty times more olfactory receptors than our puny little noses do.

"'Big Nose'?  Who you callin' 'Big Nose,' bub?"

Not only that, a dog's olfactory processing center is forty times bigger relative to the rest of its brain than yours is.  So how does that affect what neuroscientist David Eagleman calls its umwelt -- the sensory world it inhabits?  Imagine if the olfactory landscape you were immersed in every time you took a breath was as vivid as the visual and auditory landscapes most of us experience without even thinking about it.

No wonder my dogs both sniff me thoroughly whenever I come home after being away.  Who knows what information they're gleaning about where I've been, who I've come into contact, and *gasp* what other dogs I may have said hi to along the way?

We're just beginning to parse how our sensory processing centers integrate with the other parts of the brain, and solve the old question of why (and how) the olfactory sense is such a powerful trigger to sometimes long-buried memories.  Scientists are even considering the possible use of scents as a way to decondition traumatic memories in PTSD sufferers -- if there are smells with positive, reassuring connections, being exposed to those while suffering from the resurgence of trauma might blunt the edge of the pain.  In one study, smelling an odor with pleasant associations (in this case, fresh coffee) while recounting a memory of a traumatic experience significantly lowered the emotional distress of the test subjects.

It will be fascinating to see where this research goes, as we untangle layer after layer of the complex network that allows us to perceive our world and recall what we experience.  And, perhaps, explain how after fifty years, there's still a link in my brain between sweet olive flowers, old books, and my grandma's face.

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Miasma and misrepresentation

One of the (many) things that drives me nuts about woo-woos is the fact that they will take incorrectly or incompletely understood scientific research and pretend that it supports whatever goofy idea they are currently promoting.

It's why the creationists immediately go for the holes in scientific knowledge as support for the universe being six thousand years old (the "God of the gaps" idea), throwing in an occasional bit of actual science as support, and ignoring the vast ocean of evidence that completely discredits their claim.  It's why the homeopaths talk about vibrations and quantum states as if they understood what those terms mean, stopping with Deepak Chopra in their quest to find out what the scientists themselves have to say on the matter.

I ran into an especially good (or bad) example of this yesterday, when I bumped more-or-less accidentally into a concept from the woo-woo canon called "Inherited Miasma."  Here's what the Ascension Glossary has to say about inherited miasma:

Miasma is a psycho-spiritual inherited distortion created by trauma, abuse, fear based belief systems and Soul Fragmentation which, over time, was genetically encoded in human DNA, and resulted in various forms of dis-ease [sic] or imbalance.  These dis-ease patterns were then encoded and passed down in Negative Ego behaviors or DNA code from generation to generation from the genetic alteration made from the NAA influence.  Levels of the passed down distorted or flawed DNA would result in a dissipation of the original form of the disease.  The manifested diseased energy and its physical body pattern would sometimes skip generations.  The dissipated energetic pattern (cellular memories from the Ancestry or Family of Origin) of the original disease would then manifest in future generations in lesser or hybridized forms.

Which sounds pretty scary, especially when you find out that "NAA" stands for "Negative Alien Agenda," which, we are told, consists of the plans of a bunch of alien psychic parasites to use us as a food source.

If you descend from people who were oppressed at some time in history (who doesn't?), not to worry; you can get past all of this:

When one awakens, one will then need to decide what you want to energetically “wear” - as everything you inherited in your family (and the collective human race) does not have to become a part of your self-defined identity.  As you observe and take responsibility for what you are inhabiting (this is your fleshly body) and being accountable to the current station of your life circumstances, one can participate with healing your genetic and miasmatic relationships that reside as energetic memory in your flesh.  In most cases if you pay attention to the various patterns (attitudes, ideals, emotional intelligence) in your current Bio-Family dynamic, you will know these archetypal patterns extend to other lifetimes as well as hold relevant information and clues to what you agreed to heal (types of collective human miasma) while you incarnated on planet earth during the Ascension Cycle.

So yeah.  That's a relief.

What is maddening about this is that these wingnuts don't have any evidence to support their claims, and they don't need to; the claim itself is so vague that you could decide that damn near anything you experience comes from "miasma."  Headache?  It's because one of my ancestors got punched in the face.  High blood pressure?  My ancestors experienced stress that is now encoded in my genes.  No specific, testable, potentially falsifiable statements, just an evil influence stalking us from our long-dead relatives.

Convenient, no?

Miasma by Robert Seymour (1831) [Image is in the Public Domain]

Okay, now for the really maddening part.  These folks have latched on to some actual science as support for their silly pseudoscience.  A relatively recent discovery in genetics is that some variations in a population are not due to changes in the DNA itself, but due to changes in the transcriptional potential -- the degree to which certain genes are expressed.  Called epigenetics, this phenomenon often has to do with the amplification or silencing of genes in parents or even grandparents, which then affects how the children (or grandchildren) express their own copies of the genes.  It's kind of a weird twist on the ideas of Lamarck -- that in certain cases, acquired characteristics can be inherited.

A fascinating example of this phenomenon was the subject of an article in Scientific American a while back.  A study has shown that the children of Holocaust survivors have elevated levels of stress hormones.  The leader of the research team, Rachel Yehuda of the Icahn School of Medicine at Mount Sinai, found that children were influenced in utero by the stress their mothers were experiencing:

It is not completely clear why survivors produce less cortisol, but Yehuda's team recently found that survivors also have low levels of an enzyme that breaks down cortisol.  The adaptation makes sense: reducing enzyme activity keeps more free cortisol in the body, which allows the liver and kidneys to maximize stores of glucose and metabolic fuels—an optimal response to prolonged starvation and other threats.  The younger the survivors were during World War II, the less of the enzyme they have as adults.  This finding echoes the results of many other human epigenetic studies that show that the effects of certain experiences during childhood and adolescence are especially enduring in individuals and sometimes even across generations.

Note how precise the language is.  No hand-waving psycho-spiritual inherited distortions; a specific claim that elevated cortisol levels in a pregnant woman can affect her child's ability to transcribe a gene related to cortisol metabolism.  Measurable, testable, and based in comprehension of the actual science.

The unfortunate part, though, is that the "inherited miasma" people love epigenetics, the same way the homeopaths love quantum physics, because at a quick read the science appears to support their crazy stance.  They read the first paragraph of a Wikipedia article on the topic (I swear, from some of the stuff I've seen, they can't have done any more than that), and then blather on about how inheritance doesn't require DNA, our ancestors' spirits are still influencing our lives, karma, reincarnation, and off the edge of the cliff they go.

Look, it's not that I'm some kind of elite scientist myself; one of my faults is that my knowledge is a light year across and an inch deep.  I'm a generalist, a dabbler, a dilettante, or whatever other related epithet you want to throw at me.  But when I talk about something, I take the time to read what the actual non-dilettantes have learned about it, rather than picking up a ten-dollar word or two and then pretending I'm claiming something valid.  Anyone else can do the same.  What these people are doing is not only misleading, it's lazy.

And frankly, I'm glad that there's no such thing as inherited miasma.  I've done a good bit of genealogical research on my family, and some of the people I descend from went through some seriously awful times, which, given that they were mostly French and Scottish peasants, is perhaps not too surprising.  On the other hand, one of my ancestors, one Alexander Lindsay of Glamis, Scotland, apparently lost his soul to the devil in a game of dice.  So maybe there's something to it, after all.

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Forever young

At 61 I'm reaching the age where I can't deny that I'm not young any more.  By and large, though, I've been lucky.  I now need bifocals -- more to read than to do anything else, but I wear them all the time because if I don't I'll lose them, yet another fun feature of aging.  I have mild high blood pressure (controlled by medication).  A few gray hairs and laugh lines.

But overall, I'm pretty fortunate.  It's a curious thing, though, why people seem to age at different rates, and (in the broader sense) why some species age faster.  It's a current hot topic in research; why (for example) do mice mostly age out at three or four years, dogs at age thirteen or fourteen (lower for some large breeds), cats at seventeen or so, horses by age thirty, and so on?  Despite improvement in human life expectancy because of better prevention and treatment of disease, scientists haven't been able to do much about aging itself; if you are diagnosed with heart disease, you'd have a better chance of surviving now than you would have a hundred years ago, but all of the attendant features of old age proceed at the same rate they always have.

One of the biggest mysteries about aging is why some animals seem to be resistant to it.  I'm not just talking about life expectancy; even though mice and humans have vastly different life spans, toward the end of their lives they're prone to the same things -- cardiac and circulatory problems, arthritis, eyesight and hearing loss, dementia.  It's just that with mice, that whole cycle is compressed by a factor of twenty-five.  More puzzling are the handful of animals that don't seem to age at all, at least not in the conventional sense; for example, there's a hydrozoan jellyfish, Turritopsis dohrnii, that cheats death by something almost like a Doctor Who-style regeneration; it transforms itself, down to the cellular level, to the youthful (polyp) stage, then starts over from there, rendering it effectively immortal if it doesn't die from other causes.

Jellyfish are, of course, a long way from humans evolutionarily (and therefore genetically).  Closer to us are the bizarre naked mole-rats (Heterocephauls glaber) of the deserts of Ethiopia and Somalia.  They've been the focus of a lot of study -- Chris Faulkes, of Queen Mary University of London, has been looking at their weird, almost ant-colony-style social structure, and says, "They just draw you in; they’re obviously really, really cute," which I find kind of mystifying, because to me they look like a penis with teeth.

But eye of the beholder, and all that sorta stuff.

What's weirdest about these odd rodents, though, is that unlike their more familiar cousins, they have life spans of forty or more years.  But this isn't a case of simply taking the years of life, with all of their attendant ills at the end, and adjusting it accordingly; naked mole-rats simply don't seem to get all the age-related disorders.  Cardiac and circulatory problems, arthritis, type-2 diabetes, and so on, just don't afflict them.  What exactly they do die of is still a bit of a mystery, because they seem to be just as vigorous at age 35 as they were at age 5.  "Naked mole-rats are a model of healthy aging," said Vera Gorbunova, of the University of Rochester, who has been studying how they accomplish this.

She and her colleagues have uncovered some unexpected results.  What's oddest is that their genetic biological clocks -- something that all mammals have, which are indicators of age regardless of overall health -- seem to keep track perfectly well.  It might make sense to surmise that a species who cheats aging so adroitly might be doing it by virtue of a broken biological clock, but that's not what's going on here.  They have seven molecular clocks that work as good indicators of age, and in fact, two of them are also found in humans (and work the same way).  An alternative theory -- one that's being researched -- is that they are better at protecting their epigenomes (the record of alterations made to an individual's genome during its lifetime), or at fixing damage to the DNA, but both are at this point only hypotheses.

Naturally, what people are wondering is whether any discoveries of how exactly the naked mole-rats are doing this could be applied to humans.  On the one hand, increasing our life spans dramatically would do no favors for our already overcrowded Earth; but I have to say, if I could improve my likelihood of healthy aging, I'd be the first in line.  I'm not really afraid of dying, but I am afraid of debility -- I'm one of those people who loathes having to be dependent on others for my care, so some of the degenerative diseases of old age absolutely scare the shit out of me.

We're a long way from that, though, probably long enough that it won't do me much good.  So I guess I'll have to continue relying on my good diet, exercise, and a family history of long-lived people to keep me going.  Even if we find out what the naked mole-rats are doing, transplanting that into a human is going to be a considerable, if not insurmountable, challenge.

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It's obvious to regular readers of Skeptophilia that I'm fascinated with geology and paleontology.  That's why this week's book-of-the-week is brand new: Thomas Halliday's Otherlands: A Journey Through Extinct Worlds.

Halliday takes us to sixteen different bygone worlds -- each one represented by a fossil site, from our ancestral australopithecenes in what is now Tanzania to the Precambrian Ediacaran seas, filled with animals that are nothing short of bizarre.  (One, in fact, is so weird-looking it was christened Hallucigenia.)  Halliday doesn't just tell us about the fossils, though; he recreates in words what the place would have looked like back when those animals and plants were alive, giving a rich perspective on just how much the Earth has changed over its history -- and how fragile the web of life is.

It's a beautiful and eye-opening book -- if you love thinking about prehistory, you need a copy of Otherlands.

[Note: if you purchase this book using the image/link below, part of the proceeds goes to support Skeptophilia!]

Altering the message

It's always a little startling when something is discovered that ends up explaining... well, damn near everything.

If I exaggerate, it's not by much.  I'm referring to epigenetics, which is the modification of DNA or RNA by chemical changes that don't alter the gene sequence itself.  Usually this is accomplished by adding various "markers" to the strand that then change how it is expressed.  These alterations are at least sometimes inheritable; in 2008, a group of geneticists at Cold Spring Harbor came up with the definition of epigenetics as a "stably heritable phenotype resulting from changes in a chromosome without alterations in the DNA sequence," and that's pretty much the one that still is used today.

[Image is in the Public Domain]

It has led to some pretty startling discoveries.  In a paper in Nature in 2014, geneticist Moshe Szyl showed evidence that mice that were taught (using mild electric shocks) to fear an odor gave birth to offspring that feared the odor as well -- and that heightened fear response lasted for two further generations.  Szyl found that a particular olfactory gene was "demethylated" by the conditioning -- had a marker called a methyl group removed -- and this enhanced the mice's ability to detect the odor, and modified their response to it.  This led to some serious speculation that the children and grandchildren of people who had been through atrocities like the Holocaust might inherit similar enhancements, leading to significant changes in behavior.

If you think this sounds Lamarckian, you're not wrong.  It turns out there is a way to inherit acquired characteristics.  It doesn't work the way Lamarck thought it did, but there was a grain of truth in what the man said.

This comes up because of a paper in Science this week describing evidence that epigenetic marking influences everything from embryonic development to cancer susceptibility to memory formation.  In fact, one such modification -- called m6a -- can do all three depending on which RNA strand it's acting on.  The last one is the most interesting to me; a team led by Chuan He of the University of Chicago found that if you knocked out an enzyme that reads m6a in mice, they have memory defects but are otherwise normal.  They then injected a virus carrying the normal reader gene into the mice -- and the defects went away.

This sounds to me like the basis of as much of a revolution as Mendel's discovery of the gene itself, and the discovery of DNA's structure and function by Rosalind Franklin, Marshall Nirenberg, James Watson, Francis Crick, and Maurice Wilkins.  The idea that a relatively small alteration to our DNA could create inheritable changes without altering the base sequence runs so contrary to both Mendelian inheritance and the "Central Dogma of Molecular Biology" that it looks like it'll force significant revisions to every bit of genetics we thought we understood.

My guess is that they're only beginning to test the depth of this discovery.  "We just need … a lot more knowledge about these things,” He said.  "We need to stay open-minded. The field is still very young."

So maybe I need to change my declaration in yesterday's post that "the twentieth century was [past tense] the century of the gene."  If my intuition is right, we might be on the brink of a whole new chapter -- hell, a whole new textbook -- in our understanding of how genes work.  All of which reiterates something I've believed for years -- that if you're interested in science, you'll never run out of new discoveries to be amazed at.

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This week's Skeptophilia book recommendation is about a subject near and dear to me: sleep.

I say this not only because I like to sleep, but for two other reasons; being a chronic insomniac, I usually don't get enough sleep, and being an aficionado of neuroscience, I've always been fascinated by the role of sleep and dreaming in mental health.  And for the most up-to-date analysis of what we know about this ubiquitous activity -- found in just about every animal studied -- go no further than Matthew Walker's brilliant book Why We Sleep: Unlocking the Power of Sleep and Dreams.

Walker, who is a professor of neuroscience at the University of California - Berkeley, tells us about what we've found out, and what we still have to learn, about the sleep cycle, and (more alarmingly) the toll that sleep deprivation is taking on our culture.  It's an eye-opening read (pun intended) -- and should be required reading for anyone interested in the intricacies of our brain and behavior.

[Note: if you purchase this book using the image/link below, part of the proceeds goes to support Skeptophilia!]

Miasma and misrepresentation

One of the (many) things that drives me nuts about woo-woos is the fact that they will take incorrectly or incompletely understood scientific research and pretend that it supports whatever goofy idea they are currently promoting.

It's why the creationists immediately go for the holes in scientific knowledge as support for the universe being 6,000 years old (the "god of the gaps" idea), throwing in an occasional bit of actual science as support, and ignoring the vast ocean of evidence that completely discredits their claim.  It's why the homeopaths talk about vibrations and quantum states as if they understood what they were saying, stopping with Deepak Chopra in their quest to find out what the scientists themselves have to say on the matter.

I ran into an especially good (or bad) example of this yesterday, when I bumped more-or-less accidentally into a concept from the woo-woo canon called "Inherited Miasma."  Here's what the Ascension Glossary has to say about inherited miasma:

Miasma is a psycho-spiritual inherited distortion created by trauma, abuse, fear based belief systems and Soul Fragmentation which, over time, was genetically encoded in human DNA, and resulted in various forms of dis-ease or imbalance. These dis-ease patterns were then encoded and passed down in Negative Ego behaviors or DNA code from generation to generation from the genetic alteration made from the NAA influence. Levels of the passed down distorted or flawed DNA would result in a dissipation of the original form of the disease. The manifested diseased energy and its physical body pattern would sometimes skip generations. The dissipated energetic pattern (cellular memories from the Ancestry or Family of Origin) of the original disease would then manifest in future generations in lesser or hybridized forms.

Which sounds pretty scary, especially when you find out that "NAA" stands for "Negative Alien Agenda," which, we are told, consists of the plans of a bunch of alien psychic parasites to use us as a food source.

If you descend from people who were oppressed at some time in history (who doesn't?), not to worry; you can get past all of this:

When one awakens, one will then need to decide what you want to energetically “wear” - as everything you inherited in your family (and the collective human race) does not have to become a part of your self-defined identity. As you observe and take responsibility for what you are inhabiting (this is your fleshly body) and being accountable to the current station of your life circumstances, one can participate with healing your genetic and miasmatic relationships that reside as energetic memory in your flesh. In most cases if you pay attention to the various patterns (attitudes, ideals, emotional intelligence) in your current Bio-Family dynamic, you will know these archetypal patterns extend to other lifetimes as well as hold relevant information and clues to what you agreed to heal (types of collective human miasma) while you incarnated on planet earth during the Ascension Cycle.

So yeah, that's a relief.

What is maddening about this is that these wingnuts don't have any evidence to support their claims, and they don't need to; the claim itself is so vague that you could decide that damn near anything you experience comes from "miasma."  Headache?  It's because one of my ancestors got punched in the nose.  High blood pressure?  My ancestors experienced stress that is now encoded in my genes.  No specific, testable, potentially falsifiable statements, just an evil influence stalking us from our long-dead relatives.

Convenient, no?

Miasma by Robert Seymour [image courtesy of the Wikimedia Commons]

Okay, now for the really maddening part.  These folks have latched on to some actual science as support for their silly pseudoscience.  A relatively recent discovery in genetics is that some variations in a population are not due to changes in the DNA itself, but due to changes in the transcriptional potential -- the degree to which certain genes are expressed.  Called epigenetics, this phenomenon often has to do with the amplification or silencing of genes in parents or even grandparents, which then affects how the children (or grandchildren) express their own copies of the genes.  It's kind of a weird twist on the ideas of Lamarck -- that in certain cases, acquired characteristics can be inherited.

A fascinating example of this phenomenon just came out in Scientific American last month.  A study has shown that the children of Holocaust survivors have elevated levels of stress hormones.  The leader of the research team, Rachel Yehuda of the Icahn School of Medicine at Mount Sinai, found that children were influenced in utero by the stress their mothers were experiencing:

It is not completely clear why survivors produce less cortisol, but Yehuda's team recently found that survivors also have low levels of an enzyme that breaks down cortisol. The adaptation makes sense: reducing enzyme activity keeps more free cortisol in the body, which allows the liver and kidneys to maximize stores of glucose and metabolic fuels—an optimal response to prolonged starvation and other threats. The younger the survivors were during World War II, the less of the enzyme they have as adults. This finding echoes the results of many other human epigenetic studies that show that the effects of certain experiences during childhood and adolescence are especially enduring in individuals and sometimes even across generations.

Note how precise the language is.  No hand-waving psycho-spiritual inherited distortions; a specific claim that elevated cortisol levels in a pregnant woman can affect her child's ability to transcribe a gene related to cortisol metabolism.  Measurable, testable, and based in comprehension of the actual science.

The unfortunate part, though, is that the "inherited miasma" people love epigenetics, the same way the homeopaths love quantum physics, because at a quick read the science appears to support their crazy stance.  They read the first paragraph of a Wikipedia article on the topic (I swear, from some of the stuff I've read, they can't have done any more than that), and then blather on about how inheritance doesn't require DNA, our ancestors' spirits are still influencing our lives, karma, reincarnation, and off the edge of the cliff they go.

Look, it's not that I'm some kind of elite scientist myself; one of my faults is that my knowledge is a light year across and an inch deep.  I'm a generalist, a dabbler, a dilettante, or whatever other related epithet you want to throw at me.  But when I talk about something, I take the time to read what the actual non-dilettantes have learned about it, rather than picking up a ten-dollar word or two and then pretending I'm claiming something valid.  Anyone else can do the same.  What these people are doing is not only misleading, it's lazy.

And frankly, I'm glad that there's no such thing as inherited miasma.  I've done a good bit of genealogical research on my family, and some of the people I descend from went through some seriously awful times, which, given that they were mostly French and Scottish peasants, is perhaps not too surprising.  On the other hand, one of my ancestors, one Alexander Lindsay of Glamis, Scotland, apparently lost his soul to the devil in a card game.  So maybe there's something to it, after all.

Deepak Chopra and the attractiveness of nonsense

There are a variety of reasons to learn some science.  First is, it's cool, and is the only game in town when it comes to understanding what's actually going on around you in the natural world.  Second, there are some issues we're facing (climate change and genetic modification come to mind) that you can only evaluate properly if you understand the science behind them.  These issues are having an increasing impact on humanity, and most of us are coming around to the idea that handling them properly will require some deep thought -- deep thought that requires you to understand what the research actually says.

The third reason is that some knowledge of science will keep you from falling prey to purveyors of bullshit.

Take, for example, this article from Huffington Post entitled "Deepak Chopra On How to Modify Your Own Genes."  The article begins thusly:

Physician and best-selling author Deepak Chopra has an empowering message: You can actually modify your own genes through your actions and behaviors. 

Well, Dr. Chopra, it may be "empowering," but that doesn't change the fact that it's wrong.  Modifying your gene expression is not the same thing as modifying your genes.  Your body responds to changes in environmental conditions all the time -- but that is altering the expression of the genes you already have, not making any sort of permanent changes to the genes themselves.

Alteration of gene expression happens continuously, throughout our lives.  If you hadn't altered gene expression as you developed from a single-celled fertilized egg, for example, you would right now be an amorphous blob of undifferentiated cells, and you would be unable to read this post, because you wouldn't have a brain.

[image courtesy of the Wikimedia Commons]

Now, lest you think that it's just the writer at HuffPost who got it wrong, and that the passage above was taking something that Dr. Chopra said out of context and making it sound like he believes that experience alters your genes, here's an actual quote that proves otherwise:

“We are literally metabolizing something as ephemeral as experience or even meaning," Chopra said in an interview this week at the Milken Institute Global Conference in Beverly Hills, California. “If somebody says to me, ‘I love you,’ and I’m in love with them, I suddenly feel great, and I make things like oxytocin and dopamine, serotonin, opiates. And if someone says to me, ‘I love you,’ and I’m really thinking they’re manipulating me, I don’t make the same thing. I make cortisol and adrenaline.”

First off, what does "literally metabolizing... experience" even mean?  Metabolism is one of those words that's used in common parlance in a variety of ways, but for which scientists have a precise definition.  You can metabolize the protein in your dinner, but "metabolizing experience" is a meaningless phrase -- and it's almost funny that he put the word "literally" in front of it.

Chopra, of course, has become notorious for this kind of thing.  He once said, in a talk, "We are each a localized field of energy and information with cybernetic feedback loops interacting within a nonlocal field," a phrase that is kind of admirable in how tightly it packs meaningless buzzwords together.  He specializes in a style of speech and writing that I call "sort of science-y or something" -- using words like frequency and quantum and resonance in vague, handwaving ways that have great appeal to people who aren't trained in science, and who don't realize that each of those words has a precise definition that honestly has nothing to do with the way he's using them.  In fact, he's so well-known for deep-sounding bullshit that there is an online Deepak Chopra Quote Generator, that strings together words to create an authentic-sounding Chopra Quote.  (Here's the one I just got: "The secret of the universe arises and subsides in descriptions of truth.")

This hasn't diminished his popularity, though.  RationalWiki says that he has millions of followers, has a highly lucrative speaking circuit, and has written 57 books to date.

As we've seen so many times before, bullshit sells.

But back to the HuffPost article.  Here's where you have to be on your guard -- because people like Chopra and his pal Rudy Tanzi, who is a professor at Harvard Medical School and clearly should know better, have a true gift for bait-and-switch.  Throw out a little bit of science fact, hook the unwary listener, and then reel him into WooWooWorld.

The bait that Chopra and Tanzi use in the article, and also in their new book Super Brain (of course the article is free advertising for a book!), is epigenetics -- inheritable changes in gene activity that are not caused by changes to the DNA itself.  It is a new, and rapidly advancing, subfield of molecular genetics, and there have been some tantalizing experiments done that have elucidated how this can happen.  Most of them seem to have to do with phenomena such as methylation, chromosome remodeling, and RNA interference -- but the science is new and changing, and in ten years it may well be that we'll know a great deal more about how it happens, and how it effects gene expression.

I find it interesting how slyly Chopra and Tanzi slip this in.  They cite a paper by Michael Skinner et al. called "Epigenetic Transgenerational Factors of Environmental Factors in Disease Etiology" as supporting their viewpoint -- and I suspect the authors of the paper would probably cringe to find out that they'd been linked to someone like Chopra.  But if you read the actual paper, which I doubt many people did, you find the following statement:

Epigenetic transgenerational phenomena generally require the involvement of the germline to allow the transmission of an epigenetic abnormality down several generations. The ability of environmental factors or toxicants to alter the epigenome will be common in somatic tissues, but is less common for the germline because of the limited developmental period it is sensitive to reprogramming.

Put more simply: in order to be passed down, epigenetic changes have to affect your eggs or sperm, it's likely that most epigenetic changes in the organism don't.  So it's probable that some diseases are epigenetic in origin, but most of those epigenetic changes won't become inheritable.

That's a far cry from "when my brain is happy, it changes my genes," isn't it?

Okay, I know that Chopra and his ilk probably fall into the category of "what's the harm?"  He's peddling a lot of feel-good woo-woo nonsense, but so what?  Who is he really hurting?

Myself, I consider "selling an untrue view of the world" to constitute harm.  What he's telling you, at its foundation, is simply a false understanding.  And he's getting filthy rich in the process.

But if you're content to buy what he's got for sale, I suppose you have that right.  My own opinion is more in line with what Carl Sagan said years ago: "It is far better to grasp the universe as it really is than to persist in delusion, however satisfying and reassuring."