Lamarckiana

A recent study on Post Traumatic Stress Disorder (abstract here) suggests that trauma may in some cases cause epigenetic changes which switch on (or off) certain genes, for instance those pertaining to vigilance and defensive behavior, or to the immune system.

A more full account of the research lends some support to the notion that the condition investigated--the methylation or non-methylation of genes-- is unlikely to precede the occurrence of PTSD. This is important. If methylation merely correlated with PTSD, it could easily be an index of susceptibility to the disorder, rather than being itself an effect of the trauma. But, as Sandro Galea, one of the study's authors, notes,

[W]e have evidence for dose response between traumatic event exposure and methylation. The more traumatic events people have, the more methylation changes they have — which of course would [make it] unlikely that the methylation changes preceded the traumatic events.

Galea recognizes, however, that more research is needed before the results are considered established.

When I listened to the NPR report on this research, one word seemed to me conspicuous by its absence. One name, actually: Lamarck.

Lamarck, of course, was the biologist who suggested that species had evolved by virtue of changes in the individuals during their lifetimes; giraffes had stretched their necks and passed on the longer neck to their offspring. Modern further consideration of Larmack suggests that there are mechanisms by which certain instances of so-called "soft inheritance" might transpire, but Lamarck's name is still close to a hiss and a byword amongst many scientists. So it is not surprising that it would be avoided in presenting these new findings, however tentative they might be.

There is a further distinction, of course. The changes Galea postulates are not to the genes themselves, but to the mechanisms by which genes are activated. Still, it is striking to find the mainstream media suggesting that events in the organism's environment might have such an impact. After all, if a gene can be turned on or off on the molecular level by the environment, it is a very short step to saying that the gene in its new state can be passed on, or that a gene might itself be effected by environment.

This is admittedly something of an overstatement. A "short" step can still, of course, be formidable in molecular biology. Moreover, while Lamrackianism is more likely to find a foothold in epigenetic shifts as these, they are not just-breaking news, and don't by themselves constitute evidence for it, though the study of epigenetics and inheritance is still ongoing of course.

One final, more speculative note; Darwinism has recently expanded its influence far beyond the biological, not merely into the sphere of ideas (memetics), but into cosmology. Lee Smolin might be the most famous name here (followed by Quentin Smith) but many physicists now seriously consider the plausibility of cosmological accounts by which universes could be considered "fit" or "unfit", i.e., likely (or unlikely) to survive for long enough to generate sentient life. Smolin points to the similarity between the pre-Big Bang singularity and black holes to suggest that black holes might birth universes. And, since black holes also tend to proliferate in a universe as it gets older (thus letting more and more stars explode, providing the elements that go into making biological life), there is at least a plausible correlation between black holes, duration of universes in time, and the occurrence of life.

There is also an unrelated notion called "Quantum Darwinism," which hypothesizes (and produces some evidence for) the notion that the infamous transition from quantum to classical phenomena transpires by way of a kind of natural selection.

Both these notions are interesting and potentially fruitful. Always, however, looking ahead to the next step, I find myself wondering whether Lamarck may yet have a surprise for investigators of the very large or the very small.

Like many psychiatric diagnoses, Post-Traumatic Stress Disorder is controversial. There are those who oppose psychiatric diagnoses on principle, as a medicalization of what is essentially emotional or existential; to these, PTSD is an even worse offender, in that its political ramifications are many and volatile. Now, who knows, perhaps PTSD will grate on a different set: Darwinists. And maybe even cosmologists. After all, there is little that would be more traumatic than being sucked into a black hole!