Two Cultures

The mix of ideas can be a lot of fun. My favorite genetics and neuroscience people are enthused about the effects of social groups and learned behavior sequences on genetic expression.

I'm a psychologist and yawn when someone mentions learning or culture. I thought we were supposed to make our explanations in terms of the next "lower" level of understanding. Biologists refer to laws of chemistry (Eshel Ben-Jacob prefers such to mathematics as an underpinning for his observations of bacteria); the chemists likely get into physics and math.

I personally think genes are pretty cool, especially if they're not the rigid little worms we once considered them to be. I respect units that -- despite all the squishy variability they have -- probably underlie in David Teplica's observations (as reported by Lawrence Wright, pp 92-93, in "Twins."

"... freckle patterns, hair whorls, the first gray hairs, the first wrinkles on the human face, even the development of acne on the same location on the nose at exactly the same time -- all these things seem to be in some way genetically predetermined. Why would two women from Texas develop basal cell carcinoma in exactly the same spot on their left ears within a year of each other? Why would two young men from Ohio have the same extra hairs on their cheeks and the same cupped-ear deformities? How can it be that two cell clusters that were separated fifty years ago have enough information to determine where your blackheads would develop when you are fifty or sixty years old?"

From "Here Comes Granddad Again":

"If twins show these patterns, then all of us should. Denying this possibility means accepting one set of social-behavior-genetics effects for twins and a different set for the rest of us. For example, it is more than reasonable that the same effects seen in twins-reared-apart will also be seen in non-twin siblings even if reared apart. That is, it becomes likely that non-twins, reared apart from one another will also be more similar than if they had been reared in the same household. Certainly these effects will be more scattered and harder to trace than for twins but they should still exist."

Wright further relays the message that human clones will probably be more similar to each other than monoozygotic twins because twins become different from one another in partial response to combat between them in utero. Clones will not have that aggravation. Reverse the thought and consider non-twins who also did not have in utero crowding; they, like the clones, may be more strongly influence by genetic direction than if they had been one of a set of twins!

Still, some of my best friends and most frequent contacts, the biology types and the neuroscientists thrill to the variability that can be induced in the output of tiny genetic mechanisms built from protein. The observations are convincing, that genes can be tuned by environment and give a different output in different conditions.

I strongly feel it's vital that we trace those environmental influences if we are to save ourselves from repeating past human tragedies. For example, genetic tuning may dictate depression or a homicidal outcome as a function of age and hormonal status of the human performers. Low fat diets reduce coronary artery disease but life span does not increase because homicide and suicide increase, perhaps in response to those same diets.

Make us a little hungry and we want to move on; make us a lot hungry and we start to kill each other. A lot of us will be hungrier and the events that Duckett describes in South Africa will occur elsewhere.

We might compare our different interests to language. Some people learn German, others Spanish. The languages seem different but our infants respond to vocal intonation regardless of the particular tongue. The grammar appears shared despite contrasts in accents and and vocabulary. I prefer that we learn the common structure while marveling at rococo variations in detail; otherwise, we will see if we can train ourselves to sit politely still while we starve.

• Worms and Tunes by John Fentress, 11/12/98