Disclaimer: I am now retired, and am therefore no longer an expert on anything. This blog post presents only my opinions, and anything in it should not be relied on.
Thomas Verny’s “The Embodied Mind” would appear at first
glance to have nothing to do with genetics or “race”/ethnicity. It is, in fact, an interesting attempt to
argue that memory, thought, and even consciousness takes place in other areas
of the body besides the mind. However,
as part of its argument that memories can be passed from generation to
generation, it takes a detailed look at recent research in epigenetics –
including both animal experiments and human analyses. And
from this, I have concluded that it is reasonable to draw some brief initial
conclusions about the role that epigenetics plays in differential inheritance
of characteristics.
So let me lay out, first, the overall model of inherited or
socially influenced differences that I see as underlying recent research, more
or less, and then discuss how I see this research impacting our whole notion of
race and ethnicity as factors in such areas as intelligence (however defined),
success in life (however defined), and physical skills.
The Disruptive Effect of Epigenetics in Theory
Crudely speaking, I used to sense that the theory of
evolution reduced causes for differences into two: genes (which are inherited and are slow to
change because they involve mutations that “crowd out” existing genetic
structure because they are better fitted to a new physical environment) and
society (behaviors and skills learned from others, typically relatives). Thus, absent concrete knowledge of the
genome, it was possible that all differences between groups could be explained
by differences in genes, and it was possible that none of it could be explained
by genes.
The first major disruption to the wealth of research trying
to determine how much could be explained by genetics, I think, was the sequencing
of the genome. This and follow-on
research establish that 99% of the human genome is identical, and that while
physical appearance (e.g., eye, hair, and skin color) and a few diseases or
disorders (e.g., sickle-cell anemia) still
seemed to be clearly genetically based, almost everything else could not be
explained genetically by less than 10-20 “different” genes or even no matter
how many “different” genes one tried to use as a combined explanation. Moreover, when one tried to group by
so-called “race” or ethnicity, then the research tended to show that the
maximum difference in genes was between African and all other groupings, with
steadily decreasing differences between Asian, European, American, and
Polynesian groupings – clearly explained by the fact that Africans had remained
in the same physical environment over the last 50,000 years, with relatively little
cross-breeding, while the others had typically moved at least once to a
different physical environment in the intervening 50,000 years. So even where differences in genes might be
held to explain performance or skills, for all but the crudest grouping the
differences across groups were much less than the <1% maximum.
And then, along came epigenetics.
What was different and puzzling about epigenetics can be
encapsulated in one research result:
There are two groups of one species of fish in different areas of a
coral reef with absolutely identical genes – but different physical
characteristics (a skin tag in one group, no skin tag in the other).
The explanation for this, it turns out, is that epigenetics
acts like an on-off switch or cap-off/cap-on for a gene or genes. Flip the cap off, and the gene “expresses”
itself in physical characteristics in a new way; flip the cap back on, and the
gene goes back to the old “expression”.
These “switches” reside in so-called “junk” DNA, in RNA, and in proteins
associated with the workings of the genes.
And, as the research result cited above indicates, they are inheritable,
down to (as far as studies have gone) the fourth generation. What remains unclear is just how a switch
that is turned on gets turned off again; it is still possible that it only does
so via cross-breeding with those whose gene is not so expressed and/or “crowding
out” the inheritors as a smaller and smaller part of the population.
So epigenetics appears to disrupt “nature vs. nurture”
discussions, I think, in two ways:
1.
It appears at first glance to indicate that,
even if some difference in characteristics is not explainable by the action of
genes, it could be explainable by inheritable epigenetic action on genes – “genes
plus epigenetics equals destiny”
2.
Conversely, it suggests that things that have been
ascribed to genes may be explained by epigenetics happening right now – a group’s
intelligence may be improved or decreased right now by moving to a different
physical environment, and that improvement or decrease is inherited (vaguely
similar to an episode of the original Star Trek TV series where exposure to
mine air lowered intelligence and increased aggression).
The Rich Get Richer, the Poor Get Poorer
However, when I look at the research findings up to now as
presented in “The Embodied Mind”, it is apparent that the picture is much more
one-sided than it first seems.
Specifically, every research finding cited is of an
inherited epigenetic trait that is triggered, more or less, by the physical environment,
and applies to all those who are affected by that physical environment state, no
matter what their genetic differences are.
Let me restate that: no matter
what group (including male or female) I belong to, I am equally susceptible to
proneness to obesity and related disorders if my mother or grandmother
underwent prolonged starvation compared to anyone in any other group. If my mother smoked or drank during pregnancy
not only she but I will be at increased risk for cancers or alcoholism –
because those gene expressions are epigenetically transmitted to the
fetus. Of course, in the last case one
can argue that my “culture” made my mother more or less likely to smoke or drink;
but (a) that’s something that can be mitigated by changing education and social
encouragement, and (b) in most “races” or ethnicities this is not thought of as
part of the core culture. Anyway, these
are just two examples: in all other
cases cited in “The Embodied Mind”, there is no inherited differentiation based
on society at all, and therefore no role for race or ethnicity in causing
differences.
I must point out that it makes sense that it be so. It is logical that if 99% of our genes are
identical, epigenetics should apply equally to genes that are otherwise the
same and genes that are different across individuals and groups. Therefore, when epigenetics is involved, it
makes sense that 99% of the time, it is the physical environment within the
last 1-3 generations that is my destiny, and that I can very possibly change
that destiny by changing my physical environment, just as I can change things
for the better if I change my individual behavior by changing my “culture” or
social environment.
The other “theme” of recent epigenetic research is that in
many cases, it involves epigenetic switch-flipping in response to an unusually
stressful environment. Thus, starvation
during or near pregnancy is typically happening in response to lack of food
affecting not only oneself but one’s relatives or group. And that, in turn, often tends to line up
neatly with whether the group is rich/powerful or poor/powerless. We might expect therefore that an increasing
number of the poor of any race or ethnicity who is subjected to this kind of
shock will be at increased risk of diseases and disorders that affect average
intelligence as measured by standardized tests, to be less likely to have the
education that a rich person does, and to be less effective at jobs, all else
being equal. Likewise, the animal
trained to solve certain puzzles may transmit the memory of solving these
puzzles epigenetically, and therefore looks like a genetically superior animal
in terms of intelligence, and yet, give those same tests to the “poor” animal
and his or her descendants will become equally intelligent.
I summarize these two trends in epigenetic research as: The rich get richer, and the poor get poorer. Given an initial epigenetic boost, the descendants
of the rich and powerful are increasingly more likely to keep getting richer,
as epigenetic inheritance combines with the social-environment and educational
effects of being around other well-off people, while the poor’s descendants may
very well become poorer, as inherited epigenetics leads to less ability to take
advantage of education, while the social environment dominated by the powerful
rich reduces both access to education and job opportunities. And yet, epigenetic research also suggests
that these trends are reversible, to the point of epigenetic equality between
rich and poor.
Interestingly, epigenetics calls into question the seemingly
strongest research studies indicating a role of genetics in things like
intelligence and job success. Take, for example, the study that found that twins
in which one of the two was placed with a different family to grow up in tended
to reflect their birth parents’ rather than their childhood parents’ testing
success. It seemed like an obvious case
of genetic differentiation causing this result (if we assume that the
placements were not causing a child of a rich/educated or poor parent to move
to a physical/social environment in which the child was given different
treatment because of its background).
However, epigenetics suggests that it is far more likely the difference
was because of inherited epigenetic differentiation which could be reversed either
by changing the physical/social environment for this generation or by “breeding
the differentiation out”.
Getting Back to That Possible Death of Race …
So to explain why I think the research trend is to undercut the
view of individual differences being due to group differences by race or even
by ethnicity, I want to start with what the model of “evolution” of differences
seems to be turning into.
As I see it, adding epigenetics to the picture leads to a
model something like this: the five
causative factors of these differences seem to be genes (inherited),
epigenetics (inherited), the physical environment, the social environment
(culture, society, typically corresponding to ethnic or cultural differences),
and individual variation not caused by any other factor. The physical environment may also cause
genetic and epigenetic inherited differences, in the case of genetics over
thousands of years of time, in the case of epigenetics immediately.
The key question then becomes, how much of these inherited differences
can be explained by genetic differences correlated with physical appearance or
such genetically inherited traits as lactose tolerance, and how much by
epigenetics? The most likely answer, it
appears, is 90-99.5% explained by epigenetics, because if we assume 50% of
those times when we thought genes were to blame it was really epigenetics, then
for the other 99% of the genes the differences are definitely due to epigenetics
and hence if any gene is equally likely to be affected by epigenetics you get
99% x 1 + 1% x 0.5 = 99.5% of the effects of inherited differences explained by
epigenetics.
But race and notions of other group-inherited “permanent”
characteristics are inherently dependent on genetic evolution for their
validity. If inherited differences are
based on the physical environment 1-3 generations back and are easily
reversible by a different physical environment or cross-breeding, then very
little of “racial” or even “ethnic” differences is explainable by genetic or
even epigenetic “destiny”. It’s easy
visually to class people by physical characteristics; but it now appears that
inherited groupings that do anything more than that – possibly even in the area
of physical skills – will be wrong, at least 9 times out of 10.
What does that leave us with, as a guide to action? In broad strokes, the levers available to
pull to make things better have to do increasingly with the physical environment
– different exposures to disease, pollution, starvation from poverty, for
example. If we take the notion of the
rich getting richer and the poor getting poorer from epigenetics or the
physical and social environment seriously, we should primarily favor policies
that narrow the gap between rich and poor, because other research suggests that
that type of move toward “equality” will lead to a better economy and greater
innovation that drives life improvements of the future. So the levers that involve making the
physical environment more “equal” in specific ways sound like one place to
start.
I would also note that tackling group social inequities seems
to me to be a slightly better bet to pursue than before epigenetics arrived on
the scene. Whatever the apparent split
between nature and nurture before epigenetics arrived, it seems clear that
social inequities affect some differentiation between groups, and more so now
that those inequities can travel down to future generations via both society and
epigenetic inheritance – and that such epigenetics-exacerbated social inequities
can be reversed both societally and epigenetically.
I’ll add one final thought.
I haven’t touched on the whole notion of individual differentiation
across groups, inherited or not. I
really don’t think there’s enough research in the area. Still, I’ve seen enough anecdotal evidence to
form the following generalization:
Groups are more similar than you think; individuals
within groups are more different than you think.
That is, there are more men who wouldn’t mind donning a tutu
and doing classical ballet than you think; there are more women who wouldn’t
mind being bricklayers than you think; there are more white folks who like
Afro-pop than you think; there are more African-Americans who like classical
music than you think; on and on.
As I say, there is little research supporting this. Still, I think it’s a useful thing to remind
oneself of, whatever the passionate issue to which it applies.
