Is our fate locked in our genes? (Do we want to know?)

The Washington Post Sunday - - BOOK WORLD - RE­VIEW BY JONATHAN WEINER Jonathan Weiner is the au­thor of “The Beak of the Finch,” which won the 1995 Pulitzer Prize for gen­eral non­fic­tion, and “Time, Love, Mem­ory,” among other books. He teaches at Columbia Jour­nal­ism School.

Here are two new books vy­ing for our at­ten­tion, “The Gene Ma­chine” and “DNA Is Not Des­tiny.” One ti­tle is cry­ing Yes, genes are ev­ery­thing! We are our genes! and the other No, we can go be­yond them! Yes and No have been tan­gled in this sub­ject for­ever. Af­ter Charles Dar­win pub­lished “On the Ori­gin of Species” in 1859, he got a fan let­ter from his cousin Francis Gal­ton. Gal­ton asked Dar­win if he’d agree that the num­ber of ge­niuses in their fam­ily (here Gal­ton was pleased to in­clude him­self ) sug­gested the power of in­her­i­tance. Dar­win wrote back mod­estly that he thought his own con­tri­bu­tions, what­ever they might be, came from hard work. (His per­sonal motto was, “It’s dogged as does it.”) Ah, Gal­ton replied, but surely the ca­pac­ity for hard work runs in fam­i­lies, too.

In 1889, 30 years af­ter “On the Ori­gin of Species,” Gal­ton pub­lished a book called “Nat­u­ral In­her­i­tance,” one of the pri­mor­dial Yes books. There he de­clared that a gift for hard work or for “the Artis­tic fac­ulty” is man­i­festly hered­i­tary. Gal­ton wrote, “A man must be very crotch­ety or very ig­no­rant, who nowa­days se­ri­ously doubts the in­her­i­tance ei­ther of this or of any other fac­ulty.”

Gal­ton dreamed of breed­ing bet­ter hu­man be­ings through a pro­gram he called eu­gen­ics, from the Greek for “well born.” The pro­gram be­came so pop­u­lar in this coun­try that it led to a vogue for the baby name “Eu­gene.” But it also led to ster­il­iza­tion ini­tia­tives here, which, in turn, helped in­spire the Holo­caust.

To­day we know a fan­tas­tic amount about the power of in­her­i­tance, but in some ways we’re still caught be­tween Yes and No. Four­teen years ago, the Na­tional Institutes of Health and a con­sor­tium of other re­search groups around the world an­nounced that they had fin­ished read­ing the com­plete se­quence of 3 bil­lion let­ters that are writ­ten in the scroll of hu­man DNA. The ef­fort had cost a few bil­lion dol­lars and a vast amount of time in col­lec­tive per­son­hours: the equiv­a­lent of a sin­gle monk­ish sci­en­tist read­ing and copy­ing the scroll for thou­sands of years. Now the job of read­ing DNA has been tur­bocharged. It can be done for about $1,000 and takes just a cou­ple of days. Mean­while, the par­ents of many of those ba­bies know as lit­tle about in­her­i­tance as Gal­ton did in 1859. Some of them have never heard of genes. How much should new par­ents be told about what is writ­ten there?

If you have a sin­gle typo in those 3 bil­lion let­ters of your scroll of the hu­man ge­netic code — if, say, at a cer­tain point on Chro­mo­some 2, you don’t have a G but an A — then ev­ery time you bruise your thigh, your body will re­pair your thigh mus­cle with bone. Even­tu­ally your en­tire body will be en­cased in bone, like a suit of ar­mor or an ant’s ex­oskele­ton. A sin­gle typo pro­duces this con­di­tion, fi­brodys­pla­sia os­si­f­i­cans pro­gres­siva, which is ex­tremely rare.

That’s how most of us think of our in­her­i­tance. We imag­ine that, for bet­ter or worse, each bit of ge­netic ma­te­rial de­cides our fates. And that’s more or less how Gal­ton thought of it, too. But cases like these are highly un­usual, as Steven J. Heine re­minds us in “DNA Is Not Des­tiny.” Of all ge­netic dis­eases, only about 2 per­cent are caused by a sin­gle gene, like fi­brodys­pla­sia os­si­f­i­cans pro­gres­siva. In­stead, most such dis­eases are caused by vast webs of genes — some­times thou­sands and thou­sands of genes — work­ing or blundering to­gether with our ex­pe­ri­ence, our en­vi­ron­ment. And of course we may carry the genes for most of these ge­netic dis­eases with­out the dis­eases show­ing up at all.

It’s the same story not only with dis­eases, but with al­most any trait you can think of. Height, in­tel­li­gence, cre­ativ­ity, willpower: They’re all shaped by vast webs of in­nu­mer­able in­ter­ac­tions be­tween genes and en­vi­ron­ment, in­her­i­tance and ex­pe­ri­ence, in­ter­ac­tions that have hardly be­gun to be ex­plored.

Heine is a psy­chol­o­gist at the Uni­ver­sity of Bri­tish Columbia, and he’s in­ter­ested in the rea­sons that peo­ple are so eas­ily over­im­pressed by ge­netic test re­sults. What­ever we know or don’t know about this sub­ject, he says, “we are psy­cho­log­i­cally equipped to mis­un­der­stand it.” We like what one so­ci­ol­o­gist has called the OGOD frame­work — One Gene, One Dis­ease.

A few years ago, Heine con­ducted an ex­per­i­ment with a group of Cana­dian uni­ver­sity stu­dents. Most psy­chol­ogy stud­ies are done with uni­ver­sity stu­dents, mak­ing for a highly bi­ased sam­ple of the world’s pop­u­la­tion, which Heine and a few col­leagues have termed WEIRD (Western, Ed­u­cated, In­dus­tri­al­ized, Rich and Demo­cratic).

Heine had the stu­dents come to the lab and read a few news­pa­per ar­ti­cles. One group read an ar­ti­cle about “obe­sity genes.” The mes­sage: Your genes con­trol your weight. A sec­ond group read an ar­ti­cle about eat­ing and so­cial pres­sures. The mes­sage there: How much your friends weigh af­fects your weight. A third group read an un­re­lated ar­ti­cle about the agri­cul­tural pro­duc­tion of corn. Later, each student was asked to sam­ple a bowl of cook­ies. The ones who’d read about obe­sity genes ate the most cook­ies.

This helps ex­plain why we have so much trou­ble get­ting DNA in any kind of sta­ble per­spec­tive. We con­fuse it with fate, as Heine says. We imag­ine that what­ever is writ­ten in our genes is all-pow­er­ful, un­change­able, some­how of the essence. And we want to think this way. We like to think this way. It serves cer­tain pur­poses to think this way, as a head­line from the Onion sug­gests: “Obe­sity caused en­tirely by genes, obese re­searchers find.”

The NIH is ex­plor­ing the idea of se­quenc­ing the DNA of ev­ery new­born baby in the United States. There are many good ar­gu­ments for and against. But un­like the read­ing of the DNA scroll, ex­pli­cat­ing the con­tents can’t eas­ily be au­to­mated. Who is go­ing to ex­plain all of this to par­ent af­ter par­ent as the sci­ence keeps rac­ing ahead? Bon­nie Rochman, a sci­ence jour­nal­ist, ex­plores the cur­rent scene in “The Gene Ma­chine,” which, in spite of its ti­tle, is poised neatly be­tween Yes and No.

We al­ready do badly at the end of life. We don’t want to do badly at the be­gin­ning, too. At the end, all we want is a good death at home, and that’s not what most of us get. At the be­gin­ning, all we want is a healthy baby. We don’t want the ia­tro­genic gift of ex­tra ner­vous­ness. As Rochman puts it (she some­times has a mix-and-match ap­proach to metaphors), “Will it heighten the anx­i­eties of al­ready hy­per-anx­ious he­li­copter moms and dads, al­ways wait­ing for the ge­netic shoe to drop?” Soon all those he­li­copter par­ents may be wait­ing for the he­li­copter stork.

And of course ge­netic test­ing is an is­sue not only at the be­gin­ning but at the other end, too. As I wrote this piece, two col­leagues of mine at Columbia pub­lished a pa­per an­nounc­ing that they have found an as­so­ci­a­tion be­tween a gene called TMEM106B and a sud­den de­cline of the brain at the age of 65. If you have two bad copies of this gene, you’re more likely to go into that ac­cel­er­ated de­cline.

Well, maybe that’s true and maybe not. This is only a first study. But I’m 63. It would be easy to find out if I have that gene. Do I want to know?

No.

HIROSHI WATAN­ABE/GETTY IM­AGES

THE GENE MA­CHINE By Bon­nie Rochman Sci­en­tific Amer­i­can/Far­rar Straus Giroux. 272 pp. $26 DNA IS NOT DES­TINY By Steven J. Heine Nor­ton. 344 pp. $26.95

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