Wednesday, January 30, 2019

Internal Heredity and Mary Lyon’s Contribution: A Female Advantage?


We usually assign heredity to the mating of an egg and a sperm cell resulting in a set of chromosomes that will determine the characteristics of the resultant child.  But that simple picture does not explain how one goes from a fertilized ovum to producing a viable infant constructed from numerous specialized cells.  Somehow a single cell must be able to produce progeny that become muscle tissue, blood cells, lungs, brains, and so on.  There must exist some path by which this transformation can occur.  Early researchers, who did not have the benefit of modern technologies, struggled with understanding this and assumed there must be another form of heredity, “internal heredity,” that “assigned” cells the means of becoming a specific type of cell.  Thinking in terms of a form of heredity seemed appropriate because once an assignment was given, the cell and all its progeny would forever more be of the same type.  Carl Zimmer provides his readers with some fascinating insight into this process, and many other biological wonders, in his fact-filled book She Has Her Mother's Laugh: The Powers, Perversions, and Potential of Heredity.

Thinking in terms of internal heredity leads to the notion that some sort of mutation must have taken place to convert one type of cell into another.  We now know that the process is more complicated.  One might describe it as exquisitely complicated.  The basic genetic information in our cells is maintained through cell division and diversification.  What changes are the sections of our chromosomes that are allowed to remain active.

“The DNA that encodes someone’s genes is replicated in full each time a cell divides.  What makes a sweat gland cell different from a taste bud cell is the combination of genes that are active in each of them, as well as the combination that is silent.  And that difference can be passed down from mother cells to daughter cells.”

“It’s an inheritance, but not of some particular mutation.  It’s the inheritance of a state, a configuration of life’s network.  And the first glimpse of how that network is configured came to a woman whose day job was to prepare for the apocalypse.”

Zimmer is referring to Mary Lyon whose interest was in genetics.  Early experience with nuclear explosions made it clear that the radiation generated could cause damage to the genetic information stored in our cells.  There was great concern on the part of the British to learn more about how serious this might be, both because of the nuclear testing taking place, and because nuclear war seemed a distinct possibility at the time.  In 1955, Lyon was hired to work in the Radiobiological Research Unit of the Medical Research Council.  Her background and interests were in the genetics of mice.  Somehow, she managed to continue work in that area and from that would come the insight that would stimulate generations of researchers.

Lyon had access to a strain of mice that had a genetic defect.  The result for females was that they would develop a mottled coat of hair with randomly located patches of an abnormal color.  The males, on the other hand, would either have a normal coat or they would die before birth.  Since females have two X chromosomes and males have one X and one Y, this would be consistent with a defect on one X chromosome.  If the male inherited that mutation on its X it would die, if not, it would be normal.  The puzzling thing was the effect of two X chromosomes on the female.  Why did two healthy Xs not produce twice as many proteins as the single of the male and thus cause some form of disfunction?  And what caused the mottled appearance of the female coats?

Lyon’s insight was prompted by an observation published years before that cells in female cats indicated that one X chromosome was always open for business while the other appeared as a balled-up mass.  If only one X chromosome was active in females that would explain the normal functioning of females with two Xs.  But the females of the strain she was studying didn’t die so they either had to always choose to keep the nonmutated X active or something else was going on.  And the single X being operative did not explain the mottled coat of the females.  For Lyon, the only explanation that explained everything was that the females had both X chromosomes active, just not in the same cell.  At some point in its development, the females’ cells were deciding which of the Xs would be operative and which would be shut down.  Further assuming that the cells would be half one X and half the other, would explain how the females could produce enough of the needed molecules to survive the effect of the mutated gene on the one X chromosome.  The appearance of discolored patches on the female’s coat suggested that the decision of which X to utilize was made early in the development of the embryo, and that once made, all daughter cells propagated that decision so that clusters of similar cells would evolve.  Also, the fact that the coat patterns were random from female to female suggested that the selection of which X chromosome to deactivate was random.

When Lyon published her hypothesis, the general response was along the lines of “that makes sense, why didn’t I think of that?”  The goal then became to prove she was correct and to understand the mechanisms by which such genetic manipulation was accomplished. 

“The random silencing of X chromosomes came to be known as ‘lyonization’—although Lyon herself disapproved of the name.”

It was relatively simple to determine that the picture proposed by Lyon was correct.  In 1963 a researcher named Ronald Davidson studied a blood disease caused by a defect on the X chromosome.  Looking at skin cells from women who carried the defect he determined that half the cells had silenced the defective chromosome and half the functional one.

More complex is the understanding of how the manipulation of the chromosomes occurred.  That would take some time, but the understanding came.  Here is Zimmer’s description of what occurs when a cell decides which X to disable.

“A number of scientists have dedicated their careers to finding the molecules that shut down X chromosomes.  Their search has led them to one stretch of DNA on the X chromosome, dubbed Xic, where several crucial genes reside.  Early in the development of a female embryo, the two X chromosomes in each cell are guided toward each other, their Xic regions lining up neatly.  A flock of molecules descends on the pair of Xic regions, drifting between them in what is essentially a molecular version of eenie-meenie-minie-moe.  Eventually they settle on one of the two Xic regions, where they will switch on genes that will shut down the entire X chromosome.”

“One of the genes they switch on is called Xist.  The cell uses Xist to manufacture long, snakelike RNA molecules.  They slither along the X chromosome, finding a place where they can take hold.  While one end of an Xist molecule grips the X chromosome, the other end snags proteins passing by to help it.  Together, they twist and coil the X chromosome, until it has shrunk down to a compact nugget of DNA.  The other X chromosome remains active by keeping its own copy of the Xist gene silent.”

Once the selection is made the decision is permanent.  When it is time for the cell to divide, the twisted chromosome must be untwisted for the division process and then, in each daughter cell, the same X chromosome must then be again compressed into an inactive state.

This X chromosome manipulation provides an example of how what was described as internal heredity takes place.  The collection of molecules in a cell play a role in determining the functioning of a chromosome’s genes—and thus the functioning of a given cell.

“These molecules—a combination of proteins and RNA molecules—control which genes become active and which remain silent.  Some silence genes by winding stretches of DNA up tightly around spools.  Others unwind it, allowing gene-reading molecules to reach the exposed DNA.  Some proteins clamp down on a gene, shutting it down until they fall off.  Since each cell can make many copies of a silencing protein, another will soon take its place.  Cells can also shut down genes for the long-term by coating them with durable molecular shields.  This shielding—called methylation—lasts beyond the life of a cell.  When the cell divides, its two daughter cells build new shields to match the original pattern.”

It would seem that women, with their two X chromosomes, have gained an evolutionary advantage over men.  Diseases linked to the Y chromosome are clearly not a problem for them, and they are protected from most X chromosome diseases by the lyonization effect.  Males, however, have no natural recourse from defective X chromosomes which they inherit from their mothers. 

The male’s Y chromosome is mostly involved in making males masculine.  The X chromosome, on the other hand, has much more genetic activity.  Zimmer and others also entertain the notion that lyonization provides a more subtle advantage to females, one not easy to detect. 

“It may expand the scope of heredity for women.  In the brain [for example], some neurons may inherit an active X chromosome that guides them to sprout branches in one pattern, while other neurons branch in another.  The power of the human brain comes from its diversity—from different kinds of neurons, from different kinds of circuits, from different types of chemicals for communication.  Lyonization may make women’s brains inherently more diverse.”


The interested reader might find the following articles informative:







Wednesday, January 23, 2019

Intelligence and Heredity: Nurturing Our Children Is Critical


We are in an age where the human genome can be quickly and cheaply evaluated.  This allows genetic evaluations to be made to determine where genetic defects might occur that could cause serious illnesses or physical deficiencies.  There has been some success at pinpointing mutations that can lead to harmful effects.  We have also seen technology improve to the point where sections of the genome can be replaced by modified sections.  This capability has the potential to be tremendously beneficial or terribly dangerous, depending on the wisdom with which it is used.  One potential application that is often discussed is to use genetic modification to increase intelligence.  Such a goal could pinpoint abnormalities that are related to subnormal intelligence, or to boost the intelligence of a child to be born.  The first application seems beneficial, the latter, perhaps not.  It seems the best way to increase intelligence is to provide the young, developing brain a healthy environment in which it can flourish.

Carl Zimmer provides a wealth of material on the topic of human intelligence in his book She Has Her Mother's Laugh: The Powers, Perversions, and Potential of Heredity.  What his discussion makes abundantly clear is that while a component of intelligence can be traced to heredity (nature), development environment, health, and nourishment (nurture), play at least as big a role. 

“While test scores are unquestionably heritable, their heritability is not 100 percent.  It sits instead somewhere near the middle of the range of possibilities.  While identical twins often end up with similar test scores, sometimes they don’t.  If you get average scores on intelligence tests, it’s entirely possible your children will turn out to be geniuses.  And if you’re a genius, you should be smart enough to recognize your children may not follow suit.  Intelligence is not a thing to will to your descendants like a crown.”

“One reason for this complexity is that intelligence, like height, develops.  In an embryo, it does not yet exist.  Children need a few years of growth and experience before they can get a meaningful, predictive score on an intelligence test.  All along that path, experiences can influence how intelligence develops, and different experiences can lead to different intelligence test scores.”

Influences on how intelligence develops in the brain begin in the womb and continue at least through the years of schooling.  A mother subject to various forms of pollution can affect the development of her fetus’s brain.  That is why we should be concerned about the various environmental issues that drive the need for regulations.

“In 1999, Brenda Eskenazi and her colleagues at the University of California, Berkeley, went to the farming communities of the Salinas Valley to see how intelligence is influenced by the pesticides sprayed on the fields.  They followed 601 women through their pregnancies and then tracked the development of their children.  The children of mothers with the highest levels of pesticide in their blood scored low on intelligence tests they took at age seven.  And Eskenazi also found that poverty, abuse, and other kinds of adversity worsened the effects of the pesticides.”

It has long been known that a lack of iodine can cause the thyroid gland to perform poorly.  Iodine is plentiful in sea water and can be acquired from exposure to it or from food products from the sea.  Consequently, its availability varies considerably from location to location.  Iodine deficiency was known to cause goiter, a swelling of the neck, and cretinism, a form of mental disability.  For that reason, beginning early in the 1900s, iodine was added to table salt in developed countries to guard against those conditions.  It was only in the past decade that iodine deficiency in pregnant women was also linked to the development of intelligence. 

“Normally, a pregnant mother’s thyroid hormones travel into the brain of her fetus, where they help neurons crawl to their proper location in the brain.  If she has a deficiency of iodine, she makes fewer hormones, leaving the fetal brain to fail to develop properly.”

Zimmer provides notable examples.

“Sarah Bath of the University of Surrey and her colleagues documented this effect in a survey of children growing up in southwestern England.  England has never required iodine to be added to salt, in the belief that people could get enough of it in milk.  That turns out to have been wrong.  Bath and her colleagues found out that two-thirds of the pregnant women they studied had a mild iodine deficiency.  And the children of these women, Bath found, got significantly lower verbal IQ scores at age eight and scored lower at age nine on tests for reading accuracy and comprehension.”

The timing of the introduction of iodine in salt meant that the US soldiers from World War I did not benefit from the iodine, while those of World War II did.  Intelligence test data was not made available for researchers to use, but the test results had been used by the military to assign recruits to various activities.  James Feyrer, an economist at Dartmouth College, decided to determine the effect of iodine introduction on intelligence from the data available. 

“The highest scoring recruits were put into the air force instead of the ground forces.  Reviewing the records of two million recruits, Feyrer and his colleagues also checked the natural iodine levels in their hometowns.  Nationwide, the researchers found, the introduction of iodine raised the average IQ by an estimated 3.5 points.  And in the parts of the country where natural iodine levels were lowest, Feyrer and his colleagues estimated that scores leapt 15 points.”

Environmental factors have proved to be important for intelligence even when introduced after birth.

“Exposure to lead can be toxic for the brain, and up until the 1970s, American children were exposed to high levels of lead in paint and gasoline.  In 2014, Alan Kaufman, an intelligence expert at Yale, and his colleagues published a study on intelligence tests they gave to hundreds of Americans who were exposed to high lead levels before the 1970s and to hundreds more Americans who were born afterward.  They estimated that lowering lead levels in children gave them a boost of 4 to 5 IQ points.”

It is not just the chemicals that enter our bodies that can affect intelligence.  The social environment can also alter one’s measured intelligence.  It has long been known that a change in a child’s social or family situation can produce significant changes.  As far back as the 1920s, at a time when eugenics was popular and heredity was assumed to be the dominant factor, studies were being performed to counter this assumption.

“Helen Barrett and Helen Koch of the University of Chicago studied a group of children who were moved from an orphanage into preschool, where they were no longer neglected.  After six months, Barrett and Koch claimed, their test scores jumped far beyond those of the children left behind in the orphanage.”

George Stoddard and his colleagues ran a similar study in the 1930s.

“Stoddard and his team tracked 275 children who were put into foster care.  Their parents were poor, badly educated, and scored below average on intelligence tests.  After being placed ‘in better than average homes,’ Time [Magazine] reported, they scored an average IQ of 116—'equal to the average for children of university professors’.”

We now know that health and intelligence in adults can by affected by a number of adverse childhood experiences.  Poverty does not just mean a lack of access to good nourishment, it is often accompanied by a dysfunctional home life that increases the stress encountered as the brain and body are trying to develop.  This correlation was first detected in a study by the healthcare organization Kaiser Permanente.  It began surveying members with a focus on gathering information on traumatic childhood experiences.  The information collected could then be correlated with the organization’s medical records for the survey participants.  The results were tabulated for a large group that was representative of the middle class rather than having any particular association with issues of poverty.  The results were published in a paper written by Vincent Felitti and Robert Anda under the title The Relationship of Adverse Childhood Experiences to Adult Health: Turning Gold into Lead.  This work is commonly referred to as the ACE study with the acronym representing “adverse childhood experiences.”  The data showed a clear relationship between poor health as an adult and the degree of adversity encountered in childhood.  Follow up studies by other researchers confirmed that the stress induced by these adverse experiences can diminish the capability to learn and thus lower scores on IQ tests.

Zimmer describes studies with twins that further illustrate the variability of intelligence. Identical twins have as close to the identical genetic composition as it is possible to get.

“In 2003, Eric Turkheimer of the University of Virginia and his colleagues gave a twist to the standard studies on twins.  To calculate the heritability of intelligence, they decided to not just look at the typical middle-class families who were the subject of earlier studies.  They looked for twins from poorer families, too.  Turkheimer and his colleagues found that the socioeconomic class determined how heritable intelligence was.  Among children who grew up in affluent families, the heritability was about 60 percent.  But twins from poorer families showed no greater correlation than other siblings.  Their heritability was close to zero.”

But we know from Kaiser Permanente’s ACE study that poverty is not a simple socioeconomic quantity.  Such a study as that of Turkheimer’s should have also tallied childhood adversity as a defining characteristic rather than merely income.  Zimmer tells us that Turkheimer’s findings have sometimes been duplicated, and sometimes not.  The inadequacy of “socioeconomic class” as a control parameter may explain the inconsistencies.  Zimmer also provides an intriguing conclusion based on studies of European twins versus US twins. 

“A 2016 study pointed to another possibility, however.  It showed that poverty reduced the heritability of intelligence in the United States, but not in Europe.  Perhaps Europe just doesn’t impoverish the soil of its children enough to see the effect.”

Perhaps national social policies can be important.

Scientists have been sequencing DNA for several years now with little success in discovering significant genetic markers associated with intelligence.  Similar studies were performed attempting to determine the genetic basis for human height.  What was learned was that over a million markers were found throughout the entire genome and all of them had a very small effect.  It is expected that many more will be found as searches become more detailed, but there will be no one or few locations where a dominant contribution will be found.  Zimmer expects a similar result when it comes to intelligence.  Thus far the research is consistent with that expectation.

“In hindsight, searching for candidate genes was a strategy pretty much guaranteed to fail.  Our brains use 84 percent of our twenty-thousand-odd protein-coding genes.  Each type of neuron uses a distinctive combination of those genes, and it turns out the brain is made up of hundreds of cell types—so many that scientists will not finish its catalog for a long time.  To think we could just reach into this jumble and pluck out a single gene that had a clear-cut role in intelligence was to pretend we know more about the brain than we really do.”

What is striking about Zimmer’s section on intelligence is that nearly all the research presented studying the social and physical environmental factors affecting the development of human intelligence were reported in the twenty-first century.  This is mainly new research that is providing what are often alarming results.  We cannot yet claim to know all the chemicals or social influences that can alter the development of the brain and intelligence.  We should be funding biological and environmental research at an ever-higher level, yet the current administration is headed in the opposite direction.  We—and particularly our children—are being placed in danger so that a few individuals and corporations can earn more money.  That must stop.


The interested reader might find the following articles informative:












Wednesday, January 16, 2019

Wealth, Intelligence, and Longevity: Is Intelligence the Key Factor?


It has long been apparent, although not widely recognized, that wealth is associated with greater longevity.  This becomes obvious when looking at data obtained on life expectancies at age 65 by Katelin P. Isaacs and Sharmila Choudhury in The Growing Gap in Life Expectancy by Income: Recent Evidence and Implications for the Social Security Retirement Age.



It is often argued that life expectancies are increasing for both men and women, so it makes sense to raise the age for social security retirement as a means of saving money for the system.  These data clearly show that rise, but they also indicate that the poorest, neediest workers, have gained very little in terms of longevity and would be penalized by an increase in retirement age.  This wealth effect is interesting because of what it means for social security policy, but also because of what it implies for society.  One can reasonably argue that those with higher incomes have better access to healthcare and have more money to spend on healthy life styles, but it is difficult to make that correlation scientifically.  Could there be a more direct link between life expectancy and some other attribute?

Some researchers are beginning to suspect that life expectancy and intelligence are correlated.  That is one of the many enlightening insights obtained by reading Carl Zimmer’s book She Has Her Mother's Laugh: The Powers, Perversions, and Potential of Heredity.  The understanding of intelligence has been obscured by faulty early attempts to measure it.  Often tests were encumbered by cultural assumptions which penalized those with alternate backgrounds leading them to be labeled mentally deficient.  Zimmer points out that decades of improved testing indicate that an individual’s performance on different types of tests may vary, but there appears to be a general correlation in the sense that a person who does well on one type of test will generally do well on a variety of tests.  In other words, a person will possess a value for a quantity referred to as g, general intelligence.

“When scientists give people tests on different abilities, their scores are correlated.  If people are very good at recalling information from stories, for example, they also tend to do well in recalling words from lists.  Different tests for logical reasoning correlate with each other as well.  In turn, these broad abilities—such as reasoning, memory, spatial ability, processing speed, and vocabulary—correlate with each other.  Psychologists can measure this underlying correlation with a single factor known as g, short for general intelligence.”

One of the most interesting intelligence studies was performed by Scotland several generations ago.  It was interesting because it used a quality test, and because it was applied to its entire population of eleven-year-old students.  This, much later, produced a treasure trove of information as the lives of many of these children could be traced and outcomes such as longevity could be tallied.

“On June 1, 1932, the government of Scotland testes almost every eleven-year-old in the country—87,498 all told—with a seventy-one-question exam.  The students decoded ciphers, made analogies, did arithmetic.  The Scottish Council for Research in Education scored the tests and analyzed the results to get an objective picture of the intelligence of the Scottish children.  Scotland carried out only one more national exam, in 1947.  Over the next couple of decades, the council analyzed the data and published monographs before their work slipped away into oblivion.”

In 1997, a researcher studying intelligence named Ian Deary happened upon a reference to this work.  He and colleagues resurrected the tests and the data from them in order to extract as much information as possible.  For example, some of the people tested were still alive and were available for retesting to access how intelligence might have evolved over time.  Intelligence turned out to be an enduring attribute.

“…the people who had gotten relatively low scores in 1932 tended to get relatively low scores in 1998, while the high scoring children tended to score high in old age.  If you had looked at the score of one of the eleven-year-olds in 1933, you’d have been able to make a pretty good prediction of their score almost seven decades later.”

These results suggested that an early intelligence test might be useful in predicting performance in later life.  Zimmer tells us that numerous investigators attempted to look for such correlations.

“The US Air Force found that the variation in g [general intelligence] among its pilots could predict virtually all the variation in tests of their work performance.  While intelligence tests don’t predict how likely people are to take up smoking, they do predict how likely they are to quit.  In a study of one million people in Sweden, scientists found that people with lower intelligence test scores were more likely to get into accidents.”

These results suggest that general intelligence is something that is deeply rooted and affects many aspects of our lives.  The Scottish data further supported this viewpoint when it was discovered that there was a relationship between longevity and intelligence.  The more intelligent people tended to live longer.

“…Deary’s research raises the possibility that the roots of intelligence dig even deeper.  When he and his colleagues started examining Scottish test takers in the late 1990s, many had already died.  Studying the records of 2,230 of the students, they found that the ones who had died by 1997 had on average a lower test score than the ones who were still alive.  About 70 percent of the women who scored in the top quarter were still alive, while only 45 percent of the women in the bottom quarter were.  Men had a similar split.”

“Children who scored higher, in other words, tended to live longer.  Each extra 15 IQ points, researchers have since found, translates into a 24 percent drop in the risk of death.”

The second wave of Scottish youths tested in 1947 provided more easily accessible data on life outcomes and allowed for a far greater numbers of people to be tracked.

“As before, the researchers found that lower intelligence test scores raised people’s risk of death.  But when they broke down the deaths into major causes, they found the same rule held true across the board.  The people who scored in the to 10 percent were two-thirds less likely to have died from respiratory disease than those in the bottom 10 percent.  They were half as likely to have died from heart disease, stroke, and digestive diseases.”

The possible explanations for these results include the factors mentioned above for explaining longevity being greater for the wealthy: access to better healthcare (assuming they earned more income), and greater wisdom in lifestyle choices.  Some people don’t find these explanations compelling.  The researcher, Ian Deary, believes these correlations suggest an intimate correlation between exceptional brain function and exceptional body function.

“But the influence of intelligence on longevity is so broad that Deary has proposed a deeper connection.  Scores on intelligence tests may gauge some broad feature of human biology, in the same way a thermometer or blood pressure reading does.  The efficiency in the brain may have something in common with how well other parts of the body run.  And this ‘system integrity,’ as Deary calls it, may help determine how long the whole system runs before falling apart.”

Zimmer remains neutral on this hypothesis, but he does provide some information that suggests that a well-functioning brain might be an indicator of a well-functioning body.

“Our brains use 84 percent of our twenty-thousand-odd protein coding genes.”

We have encountered two sets of data.  One indicates that wealth improves longevity, the other indicates that intelligence improves longevity.  The two can be in agreement if attaining a high income is correlated with intelligence.  It is not difficult to expect such a tendancy to exist.  It is also not difficult to expect a correlation between a well-functioning intelligent brain and exceptional physical performance such as required in athletics (or piloting a lane or avoiding having accidents).  The notion presented by Deary that intelligence is an indicator of “system integrity” is intriguing, but difficult to evaluate because it depends on biology at an extremely deep level.  But wouldn’t it be fascinating if it were true?


The interested reader might find the following articles informative:





Sunday, January 13, 2019

Genetic Inheritance of Height: Can We Understand It?


Carl Zimmer has produced a remarkably rewarding book on the subject of heredity: She Has Her Mother's Laugh: The Powers, Perversions, and Potential of Heredity.  It is a brick of a book stretching to almost 600 pages, unusual for a volume aimed at a general audience, but there is not a dull stretch in it.  The length was necessary to try to do justice to all the topics that arise.  Here we will consider Zimmer’s discussion of human height and its heritability.  Height, along with intelligence, and longevity, are desirable characteristics that appear to have some degree of heritability.  This has raised the issue that we might one day have the technology to perform genetic engineering that could control positive and negative characteristics in our offspring.  Zimmer’s investigations provide some insight into how likely that is to be possible.

Part of Zimmer’s findings were covered in Average Height as an Indicator of National Social Success where the dependence on health and nourishment was examined in its historical context.  There we learned that we in the United States were once the tallest and healthiest people on earth.  However, over the past century, Europeans with their “misguided” notions of welfare and social assistance, have left us in the dust as we have descended, height-wise, to mediocrity among the wealthy nations of the world.

“How tall children grow depends intimately on their health and diet.  A child’s growing body demands fuel both to stay alive and to build new tissues.  A healthy diet—especially one rich in protein—can meet both demands.  If the diet falls short, the body sacrifices growth for survival.  Diseases can also stunt a child’s growth, because the immune system needs extra resources to fight off infections.  Diarrheal diseases are especially brutal because they also rob children of the nutrients in their food.  This fate can get locked in tightly in infancy.  As a result, the height of children at age three correlates well with their height in adulthood.”

Our personal observations lead us to believe that tall people tend to have tall children, but descriptions like “tend to” do not constitute good science.  And the effect of nurture—nourishment and health—complicates the determination of the degree to which height is heritable.  The advent of genetic mapping has provided researchers with a powerful tool to assist in their investigations.

“Peter Visscher and his colleagues found that pairs of siblings can vary tremendously in their genetic similarity, sharing as little as 30 percent of their genetic variants in common to as much as 64 percent.  If a trait is highly heritable, Visscher reasoned, then it should be more similar in siblings who have more DNA in common.”

“In 2007, Visscher and his colleagues examined the height of 11,214 pairs of regular [non-twin] siblings.  They found that…those who shared more than half of their DNA—tended to grow to more similar heights.  Siblings with less genetic similarity were not so similar.  The scientists used these correlations to calculate the heritability of height.  They ended up with an estimate of 86 percent.”

“That’s an exceptionally high figure.  Nicotine dependence has a heritability of 60 percent.  The age at which women go into menopause is 47 percent.  Left-handedness is at a mere 26 percent.  In the world of heritability, height stands tall.”

Given that our heights are determined to a considerable factor by our genetic inheritance, does that suggest that it is a quantity that could be subject to genetic manipulation?  Could parents one day pay to provide their children with the advantage of added height?

Genetic scanning has had some success at pinpointing causes for a few diseases that can be associated with defects in a single gene or in just a few genes.  However, for most diseases any correlations are too small to be easily isolated and identified.  So far that has been the case for the attribute of height as well. 

The approach is to compare genetic data at various locations in the genome for as many people as possible in order to search for correlations that can be linked to the height of the individuals.  Only a couple of genes have been easily identified that appear to have an effect on height, but these only represent a small fraction of the dispersion in heights.  Very detailed studies indicate that height is correlated with numerous locations and these are distributed throughout the genome.  These studies have required examining millions of locations in the genome of hundreds of thousands of individuals in order to identify statistically significant correlations.  Consider one ambitious study.

“…Hirschhorn’s team scanned 2.4 million genetic markers in a quarter of a million people.  They looked for variants at each of the markers with a very strong link to height—so strong that they could confidently reject the possibility that the links were just coincidences.”

“That study gave Hirschhorn and his colleagues a list of about seven hundred strongly supported genes.  But they also found many other ambiguous variants that didn’t quite meet their strict standards.”

Subsequently, a researcher named Pritchard went back and applied a more rigorous statistical approach to evaluating these ambiguous cases.

“What made this study startling was just how many of these variants Pritchard and his colleagues found.  At 77 percent of the markers they studied—almost two million spots in people’s DNA, in other words—they could detect an influence on height.  The markers were not clumped around a few genes on one chromosome.  They were instead spread out across all the chromosomes, encompassing the entire human genome.”

“Traditionally, geneticists have called height polygenic—meaning ‘many genes.’  Pritchard thinks a new name is called for: omnigenic.”

It would appear that if one wished to create taller people one must revert to the traditional breeding methods long used on plants and animals.  That is probably a good thing.


The interested reader might find the following articles informative:




Sunday, January 6, 2019

Authoritarians and the Backlash Against Female Empowerment


Much anguish has been expressed over the right-wing populists who have either gained power or threaten to gain power in their various countries.  The usual explanations for their surge in popularity include anger at lack of economic advancement and dismay at the threat of multiculturalism that will ensue if immigration is not severely limited.  Peter Beinart suggests that the explanation is more complicated and another factor is critical to understanding in an article for The Atlantic titled The New Authoritarians Are Waging War on Women (titled The Global Backlash Against Women in the paper version).  He begins his piece with this lede.

“Donald Trump’s ideological cousins around the world want to reverse the feminist gains of recent decades.”

Trump’s “ideological cousins” include the heads of state of Brazil, the Philippines, Hungary, and Poland.

“When Americans look abroad these days, they see Donald Trumps everywhere: In Brazil, whose new president, Jair Bolsonaro, endorses torture, threatens to pull out of the Paris climate-change agreement, and suggests that his country was better off under military rule. In the Philippines, where President Rodrigo Duterte has overseen the extrajudicial killing of thousands of alleged drug dealers and threatened to impose martial law nationwide. In Hungary, where Prime Minister Victor Orban has quashed the free press, enriched his cronies, and stoked fear and hatred of refugees. In Poland, whose Law and Justice Party has undermined the independence of the supreme court.”

When recorded history began, men had gained dominance.  From their positions of power, they created religions and hierarchical structures in political, economic, and family life that reinforced their power.  Female empowerment is a threat to these male cultural entitlements.

“To understand global Trumpism, argues Valerie M. Hudson, a political scientist at Texas A&M, it’s vital to remember that for most of human history, leaders and their male subjects forged a social contract: ‘Men agreed to be ruled by other men in return for all men ruling over women.’ This political hierarchy appeared natural—as natural as adults ruling children—because it mirrored the hierarchy of the home. Thus, for millennia, men, and many women, have associated male dominance with political legitimacy. Women’s empowerment ruptures this order.”

It is relatively easy to illustrate Beinart’s point with Trump’s campaign.

“He made Hillary Clinton—the first woman ever nominated for president by a major party—the personification of America’s corrupt political system. But rather than credibly promise to cleanse America of corrupting financial interests, he promised his supporters—the majority of whom told pollsters that America had grown “too soft and feminine”—a government cleansed of the corruption of one particular villainess.”

“Outside Trump rallies, vendors sold T-shirts showing Trump as a bare-chested boxer towering over a suggestively posed Clinton. TRUMP 2016. "FINALLY SOMEONE WITH BALLS read one pin."  Declared another: "DON’T BE A PUSSY, VOTE FOR TRUMP IN 2016." Inside the rallies, crowds chanted 'Lock her up,' a taunt never directed at Trump’s male primary rivals. Again and again, Trump responded to women who challenged him politically—Fox News’s Megyn Kelly, his rival presidential candidate Carly Fiorina, MSNBC’s Mika Brzezinski, Democratic Senator Elizabeth Warren—by calling them ugly. After his second debate with Clinton, he observed that she had ‘walked in front of me, and ‘believe me, I wasn’t impressed.’ The implication was clear: No matter how high a woman ascends, she’s ultimately just a body whose value is determined by men.”

Probably the best example of a Trump lookalike is Jair Bolsonaro, the newly elected leader of Brazil.

“Like Trump, Bolsonaro linked this counterrevolution to a counterrevolution against uppity women. When, as a legislator, he voted to impeach Brazil’s first female president, Dilma Rousseff—who had been tortured by Brazil’s military rulers in the early 1970s—he dedicated the vote to one of that regime’s most infamous torturers. In 2015, he told a Brazilian congresswoman, “I would not rape you, because you are not worthy of it.” Crowds at Bolsonaro rallies chanted that they would feed dog food to feminists. And, like Trump, Bolsonaro has intense support from his country’s growing population of evangelicals, who appreciate his fervent opposition to abortion and gay rights.”

Consideration of Duterte’s rule in the Philippines has focused on his violent war on drugs, but he makes no secret of his disdain for women.

“Also like Bolsonaro, Duterte has threatened violence against women. In 2017, he informed Filipino soldiers that because he had declared martial law on the island of Mindanao, they could each rape up to three women with impunity. In 2018, he told soldiers to shoot female rebels ‘in the vagina,’ because that would render them ‘useless’.”

“Duterte’s antifeminist crusade—like Trump’s and Bolsonaro’s—has also featured the ritualized humiliation of powerful women. When Senator Leila de Lima demanded an investigation into Duterte’s drug war, he vowed to ‘make her cry.’ The government then detained de Lima on drug-trafficking charges and leaked evidence supposedly proving, in Duterte’s words, that she was ‘screwing her driver’ like she was ‘screwing the nation’.”

Other autocratic leaders are better known for other political outrages, but also demonstrate similar desires to counter women’s social and political gains.

“Not all of the new authoritarians are this flamboyant. But they all link the new political order they seek to create to a more subordinate and traditional role for women. Orb├ín, who has accused his predecessors of permitting immigrants and Roma to undermine Hungary’s identity, has proposed ‘a comprehensive agreement with Hungarian women’ to bear more children. He promotes debt-free education for women, but only if they have at least three children.”

“For its part, Poland’s autocratic government has run ads urging Poles to ‘breed like rabbits’ and banned over-the-counter access to the morning-after pill. In late 2017, after Polish women protested draconian new restrictions on abortion, the government raided the offices of women’s groups.”

What does this mean for the future of women?  Does greater empowerment merely generate a greater backlash? 

Beinart provides an example of where female empowerment has become official policy that has been successfully implemented.  The Nordic countries of Iceland, Finland, Sweden Denmark, and Norway all have high representation by women in their political structures.

“Compare the United States, the Philippines, Brazil, Hungary, and Poland with the countries of northern Europe, where women’s political power has become more normal. In 2017, women made up 48 percent of Iceland’s parliament. In Sweden, the share was 44 percent; in Finland, 42 percent; and in Norway, 40 percent. In the countries that have recently elected gender-backlash authoritarians, the rates are lower, ranging from Italy’s 31 percent to Hungary’s 10 percent.”

Beinart associates Nordic rights for females with a tendency for males to take a more active role in household activities rather than allowing them to be a burden associated only with females.

“There is a striking correlation between countries where women and men behave more equally in the home and countries where women are more equally represented in government. Take Sweden, 44 percent of whose parliamentarians are women. There, the gap between the amount of housework done by men and that done by women is less than an hour a day. In the U.S., where women will soon make up roughly 23 percent of Congress, the housework gender gap is an hour and a half. In Hungary, where women account for 10 percent of parliament, it is well over two hours.”

This leads him to conclude that it may take generations for those patterns of behavior to change in the countries he has discussed.  He finishes with this comment.

“Women looking to unseat Trump or Bolsonaro in the next election may find little comfort in the Nordic example. Family dynamics change not year by year, but generation by generation. Nonetheless, the new authoritarianism underscores the importance of an old feminist mantra: The personal is political. Foster women’s equality in the home, and you may save democracy itself.”

Beinart’s interpretation of the Nordic example leads him astray.  Women in those countries did not become equal because household customs drifted towards equality.  They became equal because policies were implemented that made them equal.  Let women continue to acquire political power and they will create legislation that supports fairness between genders, and that fairness will seep into the education we provide our children and even into household activities.  It can happen quite quickly if women—all women—want it to happen.  In the United States, women, if they stick together, could take control of the Democratic Party.  And with their numbers of voters, they could control the political agenda.  It could happen quite rapidly.


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Tuesday, January 1, 2019

Interpreting the Constitution, State by State


Our federal Constitution has little to say about many of the problems that arise in a modern society.  The justices who make up the Supreme Court claim they apply an appropriate philosophy for dealing with such situations, but in practice, they are left to base their decisions on their personal beliefs about what is appropriate for the nation.  They may or may not be bound by judicial precedents, and they can be swayed by public opinion.  The Court is hesitant in directly countering an opinion shared by a clear majority of the citizens.  

Given the extreme partisan divisions in the country, the selection of a new justice can seem like an existential threat to a way of life.  There has to be a way in which democracy, the will of the majority of the people, can inform the decisions made by these nine biased human beings.  History suggests that Supreme Court rulings can be affected by related decisions reached in state courts based on state constitutions. These rulings are also made by biased individuals, but their opinions are informed by the beliefs held by the majority of the residents of their state.   Positions taken by a number of state courts can then provide both legal precedent and an expression of the will of a significant fraction of the population.  That can be difficult for a federal court to ignore.

Former Justice John Paul Stevens reviewed the book 51 Imperfect Solutions: States and the Making of American Constitutional law by Jeffrey S. Sutton in an article titled The Other Constitutions for the New York Review of Books.  Sutton describes four examples where state courts were more correct in preserving individual rights and produced the appropriate decisions before those positions were eventually reached by the Supreme Court.

“These examples demonstrate that the law may be best served if proponents of a new or expanded right give priority to a claim based on their state constitution, and that state judiciaries can set an example for the federal judiciary. Each of them—as well as a fifth example, regarding partisan gerrymandering, that Judge Sutton does not take up but is also worthy of study—merits separate discussion.”

The first example discussed by Sutton involved the funding of public education.  When the Supreme Court ruled against officially designated segregated schooling in Brown v. Board of Education (1954), it did not address the fact that states could effectively continue to impose substandard education on blacks by controlling the amount of money spent in a given school district.  In fact, unequal educational funding was the subject of a suit brought against the state of Texas, and the Supreme Court sided with Texas and refused to insist on greater equality in state funding.

“In San Antonio Independent School District v. Rodriguez (1973), over the dissent of four justices, including Thurgood Marshall, the Court rejected a challenge to Texas’s school-financing system, which was based on local property taxes and thus created wealth-based barriers to equal educational opportunities in Texas’s public schools.”

Incredible as it might seem today, it would be the Texas Supreme Court that would ultimately rule that unequal funding was unconstitutional according to the state constitution.

“The plaintiffs received no relief in their federal case, but in three cases in the 1980s and 1990s the Supreme Court of Texas held that the state’s school-financing system violated the Texas Constitution. Courts in other states, like New Jersey and Ohio, have similarly held that their state constitutions require some measure of equal funding among school districts, demonstrating that state constitutions sometimes offer greater protections than the US Constitution does.”

A second example involves the use of evidence obtained by unconstitutional means in criminal trials.  Many states, but not all, had concluded that such evidence was not admissible.  These opinions influenced the Supreme Court to take a similar position.

“In Mapp v. Ohio (1961), the Supreme Court, noting the states’ “impressive” experience with such a rule, established that the exclusionary rule applies to evidence obtained as a result of an unreasonable search or seizure. Twenty-three years later, the Court established a good-faith exception to the exclusionary rule so that, if police officers reasonably rely on a warrant that is later found to be invalid, the evidence obtained pursuant to that warrant need not be excluded from trial.”

Stevens indicates a different lesson is to be drawn from Sutton’s third example.  In the early twentieth century the supposed “science” of eugenics was widely supported.  It was generally believed that mental disabilities, crime and unsocial behavior were hereditary qualities and the nation’s integrity was being compromised by allowing in so many immigrants with inferior characteristics into the nation.  The obvious solution was to prohibit any individual deemed “feebleminded” from procreating.

“Many national leaders at that time—including, for example, Theodore Roosevelt and John D. Rockefeller—believed that the genetic quality of the human population could be improved through selective breeding. Many eugenicists thus advocated the forced sterilization of people whom they viewed as inferior members of society, such as the mentally ill, the immoral, and the criminally inclined. In Buck v. Bell (1927), Justice Oliver Wendell Holmes wrote an opinion joined by all but one of his colleagues that upheld an order approving the sterilization of a woman who medical authorities claimed was ‘feebleminded’.”

Prior to this federal decision, many state courts had ruled against forced sterilizations.  The effect of the Supreme Court ruling was to inhibit state courts from coming up with counter opinions.  The opportunity to obtain protection via state courts still existed, but subservience to the federal ruling eliminated those opportunities.  The practice of eugenic cleansing disappeared not because of the US Constitution, but because Adolphe Hitler took it to its natural conclusion.

“In this case, the Supreme Court’s decision had the effect of dissuading state courts from protecting individual rights as robustly as they had been protecting them before Buck v. Bell, underscoring the potential danger of focusing exclusively on federal rights and federal courts.”

Sutton’s final example involves forcing students to pledge allegiance to the American flag.  This practice might seem for many to be unnecessary and inappropriate for an educational setting, but for Jehovah’s Witnesses it was totally unacceptable.  Yet, the Supreme Court ruled that schools could compel children to participate.

“…Justice Felix Frankfurter’s opinion for the Supreme Court in Minersville School District v. Gobitis (1940) authorized schools to compel students to salute the flag. Following that ruling, hundreds of Jehovah’s Witnesses were attacked across the country.”

Some states accepted the federal ruling, but many did not.  The Supreme Court was forced by the discord to come up with a new ruling.

“Although many state courts reached a conclusion similar to that of the Supreme Court in Gobitis, several prohibited such compulsion and thus set the stage for Justice Robert Jackson’s opinion overruling that decision in West Virginia Board of Education v. Barnette (1943).”

Stevens suggests a similar evolution in federal constitutional interpretation may be taking place with regards to the practice of gerrymandering legislative districts.

“Although the Supreme Court has been unable to find in the US Constitution manageable standards for judging the permissibility of partisan gerrymanders, state courts are not foreclosed from construing a state constitutional provision as mandating impartiality. In other words, state law may well offer an effective remedy against partisan gerrymandering regardless of whether federal law does. Indeed, just this year, in League of Women Voters v. Commonwealth of Pennsylvania, the Pennsylvania Supreme Court held that the state’s gerrymandered congressional map violated the state constitution. In light of the continuing uncertainty about when, if ever, the Supreme Court will identify federal standards for judging the constitutionality of partisan gerrymanders, it is particularly important for voting rights advocates to look to state courts and constitutions in mounting such challenges.”

This discussion invites the reader to consider other areas in which state or local activism resulted in shifts in constitutional interpretation.  Legalization of same-sex marriage would probably fall in that category.  Legalization of marijuana by states for both medical and recreational purposes is growing and producing pressure for some sort of accommodation at the federal level to occur.  The growing popularity of imposing national healthcare policies, as in the Affordable Care Act (Obamacare), may protect that program from judicial death and could pave the way for a more functional and efficient national system.

So, keep the faith all of you who feel the need to be a part of some form of a “resistance.”  There are more ways than one for activism to succeed.

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