The genetics-solves-everything crowd is continuing to have an influence on society that threatens to set Americans' notions of equality back decades. I still believe these attitudes are cyclical, but it is always depressing and disturbing to be in the regressive part of the cycle, with no hint of change in sight. The target now of course is public education - always in the sights of extremists, whether it involves adding prayer, subtracting science, or the current fad, teaching kids their gender roles, as if society weren't taking care of all of these things adequately outside the classroom.

Dr. Leonard Sax's website is called "Why Gender Matters". His publications have such objective scholarly titles as "Reclaiming Kindergarten: making kindergarten less harmful to boys" (Psychology of Men and Masculinity, American Psychological Association, 2(1):3-12, 2001), which like his other writings set up an absurd dichotomy between boys and girls as if they are unrelated species. He claims that for boys, but not girls, kindergarten is "a series of alienating failures and humiliations" and implies it is thus the end of their academic careers. Many women competing for professional jobs (requiring extended education) with men would be surprised to hear that all males' spirits were crushed in kindergarten, given that they are still pretty much running society.

The problem with our educational system is not that "no one is teaching them how to be men and women" (from Sax's website) but that we are using blunt instruments, such as standardized testing, which saps what little autonomy teachers had in the classroom before NCLB. This means they are unable to address differences among individual students in development times of different skills. Yes, that variation exists, but using gender as the blunt instrument to guide education reform is even worse than using a standardized test. On top of it being a pointless exercise to assume anyone's academic strengths and weaknesses at a given age can be assessed using their appearance, it also reinforces so many stereotypes that so many of us had finally begun to move past, and furthermore gives them false "scientific" credibility. This type of "science" is no different from attempts a century ago to demonstrate through physical qualities that blacks were less intelligent than whites.

This blog has previously summarized the alarming trend of claiming genetic origin for every trait anyone can think of, and why the papers supporting these ideas tell us absolutely nothing. The problem of the other type of research cherry-picked by Sax to support his agenda is that it studies already-developed human beings. Anyone who has raised a child should understand the intellectual dishonesty of claiming that behavioral traits possessed by a baby or toddler are clearly genetic. Humans are social creatures, programmed from birth to learn from other humans how they should behave. That includes identification with a particular gender, and all the traits associated with it in a particular society. Brain development does not occur in a vacuum, but is affected by experience. Brain-scan differences even in a newborn can not be determined to be genetic, because the newborn's brain started developing nine months before.

Most important though, the differences found are minor and slight - meaning it is unlikely that they are biologically significant. From the Times magazine article:

Sax initially built his argument that girls hear better than boys on two papers published in 1959 and 1963 by a psychologist named John Corso. Mark Liberman, a linguistics professor at the University of Pennsylvania, has spent a fair amount of energy examining the original research behind Sax's claims. In Corso's 1959 study, for example, Corso didn't look at children; he looked at adults. And he found only between one-quarter and one-half of a standard deviation in male and female hearing thresholds. What this means, Liberman says, is that if you choose a man and a woman at random, the chances are about 6 in 10 that the woman's hearing will be more sensitive and about 4 in 10 that the man's hearing will be more sensitive. Sax uses several other hearing studies to make his case that a teacher who is audible to boys will sound too loud to girls. But Liberman says that if you really look at this research, it shows that girls' and boys' hearing is much more similar than different. What's more, the sample sizes in those studies are far too small to make meaningful conclusions about gender differences in the classroom.

Why is it now acceptable to use "science" to foster people's underlying prejudices about gender, but no longer about race? Apparently there is some sort of hair-splitting going on in the minds of these "scientists" that of course skin color and other associated traits tell you nothing about what is going on in someone's brain, we know that now, so forget about that. But different genitals, now that clearly must be correlated with brain function. Especially the genitals of pre-pubescent humans!

It is especially insidious that the idea being promoted is just a new version of "separate but equal", which as anyone knows who is at all familiar with history, means anything but. Sax's motivation is clear. He has been on a crusade for years to convince people that public education is biased against boys because most of the teachers are women. (Of course, who is responsible for that? Surely not the men who over the ages told women that the only profession they could have was teaching, since obviously it is such an undesirable job. Surely not the principals and superintendents who for some reason are still overwhelmingly male, and oversee overwhelmingly female teaching staffs. But I digress.) He does a clever job of convincing people that he cares about girls too, but this concern is nothing but pandering to get people to buy into his system of segregation.

It's truly a shame, because for completely opposite reasons, single sex classrooms in public schools can be a good idea. For instance, in the context in which many kids are more interested in what the kids of the other gender think of them than the academics going on in class, single-sex classrooms can remove a major distraction. Because it's a good idea for kids to learn to relate to the other gender socially, it seems that the best situation is some, perhaps not all, single-sex classes in coed schools. It also does help remove some teacher biases which have usually been documented to favor boys (not girls, as Dr. Sax claims) in their participation. But if, as Dr. Sax claims, the majority of schools going to single-sex classes are basing their new paradigm on his "genetics" theories, then we are in big trouble, because it will make many of the gender prejudices that have sunk below consciousness openly acceptable again.

Labels: brain, education, gender, genetics, statistics

A paper discussed in an earlier post (Alford et al., 2005) relies for much of its justification on a series of papers by Thomas J. Bouchard and coauthors. An expansive claim for genetic heritability of all sorts of behavior and attitudes is found in Bouchard and McGue (2003). Frankly, the arguments made are even more disturbing in this paper.

Why disturbing? What is truly the harm in scientifically separating out the genetic and environmental influences on everything from social attitudes to "vocational interests"? The harm is that such papers serve no function other than to fan the flames of bigotry.

We are likely not yet at the crest of the pro-genetics wave. There are more and more studies being published which claim genetic bases for all sorts of traits (e.g. politics, aversion to new foods, obesity). One walks a precarious path interpreting the actual significance of this work for the general public, who is under the mistaken impression that scientists know far more about human genetics than they actually do. The mainstream media certainly tends to work more as a blunt instrument than as a nuanced filter of published scientific studies, happily being used by authors and journals who have a strong self-promotion agenda.

The straw man constructed by the pro-genetics crowd is that obviously genetic variation exists or we would all be the same. But of course it is biological significance of genetic traits that matters, not whether or not the variation actually exists. Even the most rigorous study that shows valid statistical significance for variation in a trait does not necessarily demonstrate biological significance - in fact, the huge sample sizes often used in these studies, which has the intended effect of increasing the chance of reaching statistical significance, undermine arguments for biological significance (see figs. 1 and 2). If it takes a survey of 10,000 people to detect a difference, then there is clearly so much overlap in the groups being compared that the authors should be hard-pressed to convince anyone that it matters. A slight fluctuation about the mean is much more likely to be amplified into statistical significance, although the direction it is significant is determined randomly. This was brilliantly demonstrated in a pair of papers about birth order and IQ.



Where do all the heritability estimates come from? For example, Bouchard and McGue report "heritability of IQ is about 50%." This of course is based on twin studies. But the logic used by all of these authors (none of whom I have encountered so far are actual geneticists) to produce such an exact value of genetic heritability is flawed. They make the assumption that if you compare differences in scores on surveys between fraternal twins with the differences between identical twins, that difference is the genetic component of the trait. This assumes that the environment in which fraternal twins are reared is as similar as the environment for identical twins. This assumption has naturally been both challenged and defended, but for the moment, let us concede it as valid. That leaves us with the corollary assumption that the difference between fraternal differences and identical differences is therefore entirely genetic. This is where the problems with these studies lie (discounting the obvious problems with using tests or surveys - which are biased by authors, affected by mood of the taker, etc. - to make sweeping statements about genetics).

Identical twins not only share a genotype, but also a phenotype - they look the same. As explained in the previous post on this topic, how you look is going to affect your social attitudes, not to mention self image, mostly because of your interactions with other people, who clearly behave differently to people who look different. Until a study is conducted in which one half of 30 identical twin pairs has a dramatically altered appearance (e.g. is in a wheelchair or has had major facial reconstructive surgery), all the twin studies (even those in which the identical twins were reared apart, long a mainstay of the pro-genetics camp) declaring the percent genetic contribution for any subjective phenotypic trait will be meaningless.

These papers harken back to the dark days of phrenology and craniometry - the methods employed are no more scientific, because we know no more about how genetics affects these traits now (more than mere speculation) than we did back then about how the brain functioned. But, the results are used by those who are racist or sexist to defend their views. All traits are a unique combination of usually complex genetics and environment. There is no way to establish that a person a particular "genotype" for intelligence or social attitudes, and even if there were, the expression of that trait will be dependent on the environment in complex ways that are not easily measured. Most important, because of the huge overlap in any trait associated with the brain across all types of people, for any given individual, there is no way to determine what part of their intelligence, personality, or skills are based on their appearance, even if there actually is a true statistical difference in these traits for different races or sexes (Fig 2.). But studies such as these are used by people who wish to have their stereotypes confirmed "scientifically," and frankly one has to wonder if the authors are not such people themselves.


References

Alford, J.R., C.L. Funk, and J.R. Hibbing, 2005. Are political orientations genetically transmitted? American Political Science Review, 99:153-167.

Bouchard, T.J., and M. McGue 2003. Genetic and environmental influences on human psychological differences. Journal of Neurobiology 54: 4–45.

Labels: environment, genetics, humans, statistics

Isn't parenthood supposed to be about raising a kid to be a healthy, happy, independently functioning, contributing member of society? These distorted, egocentric days in Yuppieville, it seems instead to be all about the reproductive process, rather than a far-off endpoint, that bolsters the parent's self esteem. All the issues surrounding having kids -- when, how, and not to mention whether -- focus on the parents' wants and needs, as if they were choosing the car which best projects their self-image.

Here's a woman who, after struggling with health problems that threatened her ability to get pregnant, was able to give birth to a healthy boy at age 40. One would think she would feel extremely fortunate. Instead:

"I had my sense of self-worth tied up with having a 'normal' family," Deborah explained. "You know, the family with two children. It was always this destination to be counted upon. It was what made tolerable all the losses along the way, the surgeries, the ostomy bags, everything. So when this path felt threatened, all those other losses suddenly took on more substance."

...days before the process was to begin, she found herself lying awake nights, frantic over whether she was doing the right thing. "What gets to me is that the three of them would be genetically related," she said, "and I would be the one. . . . It's not about passing on my genes. It's that I don't want to be an outsider in my own family. I don't want to feel less legitimate in my child's eyes."

If not sharing genes somehow makes this woman an "outsider in my own family," than clearly it is about passing on genes. In one sense this woman cannot help but feel this way. She wanted to adopt a second child, but her husband, who claimed he didn't have enough time to spend with the son they already have, insisted that the next child must share his genes. These people are both trapped into their views of what is "normal" reproductively. Do they put as much thought into actually raising these kids?

Before starting our donor cycle, my husband and I met once with a social worker, a standard requirement for couples using donor eggs -- though, again, not for those using donor sperm. Her job wasn't to screen us (she did, after all, work for the clinic and had little incentive to reject anyone) but to help us imagine how the genetic asymmetry might play out.

Do you know why it is not required for sperm donation? Because most men do not freak out about using donors the way that women do (excepting the jerk above who obviously thought his manhood was in jepoardy if the child was not his genetically). Using donated sperm has been common for much longer, so maybe it is just a lag in how used we are to these technologies. But in general, it is women who seem to obsess over these issues, and read deep significance into every possible stage of the reproductive process. One of the most absurd examples I have encountered was a remark made by a woman who had given birth recently by emergency cesarean section. Referring to my own c-section, I was corrected by her: "You should say 'cesarean birth' so that it affirms that you gave birth to the baby." I could only stare open-mouthed. I hauled my kid around in my guts for nine months (most of which time her presence made me miserable), and this woman actually thinks that someone out there thinks I did not really give birth because the baby didn't exit through my vagina? She was in me, and then came out. Even it had been through my nose, I would certainly define that as "birth."

But in a sense perhaps the woman was right. She either said what she did because she is pathetically insecure, or because in her mind a vaginal birth was somehow superior or more valid. My own doctor was needlessly apologetic when he informed me of the necessity of my having a cesarean. I read a parent magazine article that actually discussed making the choice to attempt a vaginal birth of a breech baby as if it were a positive thing.

It is not convincing to suggest that safety due to protection from surgery is an adequate reason for making such a choice. In a western hospital, complications from a cesarean are not much more common than those from vaginal birth. From the baby's perspective, however, it is significantly more dangerous. I am close to someone who was a breech delivery, and became slightly brain-damaged as a result of being choked by her own umbilical cord. Why any mother would put her own desires (this does not include maternal health risks, which are a separate issue) above what is safest for the baby is beyond me. But such desires have fed the growing popularity of giving birth at home (also promoted by articles in the same magazine), and underwater in birthing tubs.

The egg donor article continues:

"People see a child in a supermarket checkout line and almost reflexively make some comment about who he looks like or doesn't look like," said Robert Nachtigall, an adjunct clinical professor of obstetrics, gynecology and reproductive sciences at the University of California, San Francisco and a co-author of the paper. "We interpret it as a kind of shorthand by which people validate the child's position in the family, in society, by basically making comments that refer to the blood relationship that must exist between the child and his or her parents. The problem for people who have conceived with donor gametes is that they know it's not true. And the dilemma for them is how to respond, if at all."...The difference is that there's widespread cultural support for adoption in a way there isn't for donor conception.

So we are supposed to have special sympathy for those who make the choice to spend $40,000 on an ovum rather than a child? Why is it anyone's business in the first place? What happened to smiling and nodding politely? The answer is that they want to make it everyone's business because they have a bizarre need to have their choice "validated" by strangers. If the process of reproduction affects the child's "position in the family, in society" it is a self-fulfilling prophecy caused by constant parental worry. Plenty of adoptive parents have a good laugh when well meaning strangers remark on how their child resembles them. It happens all the time.

Resemblance talk did something else, too: although emphatic that it didn't change their love for their child, mothers said it was a constant reminder of their own infertility.

Granted, there certainly is something biological in people's obsession with fertility. After all, if we did not prefer to raise our own genetic child to raising someone else's, our genes would not get very far. Women may be more easily obsessed with reproduction than men because their investment in children is nearly always much larger than men's (the sole exception being a stay-at-home father of an adopted child). But humans have transcended a lot of base biological urges culturally. Killing is illegal among humans because with our rational brains we can project consequences, and we raise ourselves to a moral standard above what we grant to other animals. Humans also have other ways of leaving a legacy than simply by reproduction. As Stephen Sondheim once pointed out, we gain our immortality through both "children and art." Or an invention. Or a business. A strong biological urge to reproduce genetically should be tempered by the rational knowledge that the successful upbringing of a contributing member of society, carrying our heritage, is more important than whether he or she carries our genes. There are millions of adoptive parents out there who know that their kids are their kids, no matter who gave birth to them. How many abandoned mothers refer to their absent children's fathers as "sperm donors"? How many people want to disown their own rotten (but genetically related) kids?

These angst-ridden women who dwell on such superficial issues should get over themselves, but the truth is that most will not. What we should be concerned about is not how complicated genetic relationships will "play out," but rather that such self-absorbed women are raising kids at all, and for what purpose.

Labels: gender, genetics, health, humans

Go to Geek Counterpoint for the latest Tangled Bank installment, addressing topics from genetics to exoplanets to the continuing discussion about Wikepedia's accuracy.

Labels: carnivals, ecology, environment, genetics

There has been continuing interest in the case study known widely as the "German super baby." I did a brief post in November linking to the New Scientist article based on the original journal paper (Schuelke, et al., 2004. Myostatin Mutation Associated with Gross Muscle Hypertrophy in a Child. New England Journal of Medicine 350:2682-8), but did not read the original paper and related literature at the time.

As the New Scientist article summarizes, a single point mutation in the gene coding for the protein myostatin causes the condition, which appears to be partial in the boy's mother, who has one mutated allele for the gene, and more dramatic in the case of the boy, with both alleles mutated. Myostatin's function is to inhibit muscle development, and the mutation produces a non-functioning version of the protein. Thus, muscle development continues without inhibition.

Why do we have a protein to inhibit muscle development? Because it is just as important in development to turn processes off as it is to turn them on. If a system in the body is out of proportion to the rest of the body systems, there can be trouble. There always looms the possibility of future health problems, when one's body is out of whack. For example, I found this comment (authenticity unconfirmed, but compelling nonetheless) by "Kangarooistan Man" on a page discussing the condition:

...my father and I both have the "superbaby" mutation. severe myostatin deficiency. My father's bones are near unbreakable and he became locally famous after lifting a minivan.
His strength is comparable to between 3 and 5 normal men and his strength peaked at about the age of 40. His brother Joseph is suspected of having the mutation as well.
Our muscles grow at incredible rates, but don't grow much larger. The muscle fibre packs tightly- so tightly in fact that they tear under their own strength, causing us to suddenly collapse for no apparrent reason with massive muscle tears.
We have body fat of >1% and abnormal muscle definition.
...my father once jokingly held a washing machine in his outstretched arm, obviously considerably more than this 10 lb from the 4 yr old.

I don't know what we are really capable of, but I can tell you from experience that myostatin deficiency is not always a benefit. The constant pain from muscle growth and the inevitable tears that follow are horrendous and it is suspected that the huge muscle mass presses on our blood vessels, forcing blood pressure up and making our hearts less effective.

I'm sure warnings like this will not prevent the next generation of athletes from using whatever "myostatin inhibitor" someone will eventually manage to produce and put on the black market.

Of course, there could be legitimate uses in humans for such a drug, and an obvious discussion has ensued for potential treatment of conditions such as muscular dystrophy. As some researchers in the New Scientist article point out, however, the problems associated with MD are more complicated than just weak muscles, so myostatin inhibition as a treatment is likely still many years away. But, there has been some success in trials using mice with a condition analagous to muscular dystrophy in humans (Benabdallah, B. F., Bouchentouf, M. and Tremblay, J. P., 2005. Improved success of myoblast transplantation in mdx mice by blocking the myostatin signal. Transplantation 79:1696-1702).

What was most intriguing to me about the results of my journal search on "myostatin mutation" was that most papers involve research on livestock. There are breeds of cows with "double muscling" that have this mutation, which is attractive to beef producers. It was in this context that several mutations in the myostatin gene were originally identified in 1997 (McPherron, A. C. and Lee, S. J., 1997. Double muscling in cattle due to mutations in the myostatin gene. Proceedings of the National Academy of Sciences of the United States of America, 94:12457-12461). The discussion involves how the information might be used to manipulate the genetics of other farm animals similarly. The idea that myostatin's function is specifically as muscle growth inhibitor was apparently not introduced until 2002 (Kocamis, H. and Killefer, J., 2002. Myostatin expression and possible functions in animal muscle growth. Domestic Animal Endocrinology 23:447-454). Texel sheep, a "meaty" breed, apparently have a similar mutation as that identified in the human case, a single point mutation of G to A in a myostatin allele (Clop et al., 2006. A mutation creating a potential illegitimate microRNA target site in the myostatin gene affects muscularity in sheep. Nature Genetics 38:813-818).

As far as I can tell, that sums up the majority of what is known about myostatin. I predict that in a decade or so we will be hearing about a big MI (myostatin inhibitor) ring being broken up, as high school and college kids feel pressure to use it in order to compete, but start collapsing due to muscle tears and circulatory problems. Until the societal and material rewards of a stellar education surpass those of stellar athleticism, the performance enhancement arms race will continue... but that is for another rant, at another time.

Addendum: Apparently there are already a lot of supplements marketed to athletes as "myostatin inhibitors." It is clear from the literature, however, that such a drug has yet to be developed. Fortunately, some sites are honest enough to steer people away from the latest patent medicine.

Here are some pictures, real or not, purporting to show myostatin-deficient animals and humans.

Labels: genetics, humans

We have two male black and white cats (also known as tuxedo cats, or holsteins), shown here. The older one, Ippy, is well known in the neighborhood for playing with kids in the park a block away, and following people walking by our house to the grocery store across the park, waiting for them outside, and walking with them back to our house. Ippy was almost a year old when he adopted the younger, Tacaribe, without involving us in the decision (Tacaribe had two cameos on Tigerhawk soon after Ippy adopted him).

We had already discussed the interesting behavior of the black-and-white males with our vet, who told us that every single one she had run across had a very playful, mischievous and outgoing personality. She thinks it is much more pronounced in the males than the females. My husband's family had a black-and-white that was very similar to Ippy in his personality. He was people-centered rather than place-centered, which is uncommon in cats (a solitary species). For example, when they traveled and stopped in hotel for the night, they could put him out and he would come back to their room in the morning. We have come to the conclusion that the trait involved with such behavior is probably one that causes neoteny, or retention of juvenile (kitten) behavior in the adult.

This is not a particular breed of cat; Ippy and Taca have very different body types, and really only are similar in their coloring and spunky behavior. Looking in a big cat book at a book store once I noticed that many listed breeds had a black-and-white form, generally distinguished by a mostly black cat with white feet, chest/belly, and often forehead spot. For some reason, this behavior seems to be associated with this particular black-and-white coloring. Although this might seem a strange association, it is not unheard of. In Drosophila, the yellow gene, which is involved with the production of melanin (pigmentation) in the flies, also has neurological effects. Mutant males without the normal yellow gene have lower mating success than normal males, and there are apparently effects on larval foraging as well.

Behavioral neoteny in flies wouldn't really make much sense, because flies undergo complete metamorphosis - there wouldn't really be a way for an adult to act like a larva. But it is intriguing that there seems to be a similar connection between pigmentation and behavior in my cats.

Labels: behavior, cats, flies, genetics

As more and more Neanderthal DNA is discovered and made available for anaysis, it's easy to envision a new typing service: How much Neanderthal DNA do you (or your loved one) have? This is a question many have sought to answer, and I'm sure that soon you will have your chance.

Labels: genetics, humans

This kid is only 7 now, so we may hear more about him in the future. Be sure to test your kid with 10-lb weights. Perhaps s/he has the potential to become a governor some day.

As a corollary, there appears to be a mutation in cats with the opposite effect - i.e., a disproportionately high fat to muscle mass ratio. Such cats are incredibly dense yet function primarily as pillows. Clearly it is a genetic condition (according to my cat Tacaribe, at least).


There is a more recent post with some details about this condition here.

Labels: genetics, health, humans