In 1990 the Human Genome Project set out to map the basic genetic makeup of our species. Celera Genomics, a private, for-profit corporation, eventually challenged the international nonprofit undertaking represented by the Genome Project and began its own effort. In June 2000, the Genome Project and Celera made a joint public announcement that they had successfully mapped about 90 percent of the genome, with the rest to be completed shortly.

Those involved with the Genome Project reject any connection with the all-encompassing biological determinism that was at the core of hard-line eugenics. While they hope to produce significant therapies for genetically influenced or controlled diseases, they deny any wish to revisit the kind of reductionism that seeks the roots of every human quality or quirk in a single gene or a set of them.

Nonetheless, some skeptics question the purposes and consequences of the final sequencing of human DNA. In a collection of essays titled It Ain’t Necessarily So: The Dream of the Human Genome and Other Illusions , published last year, Richard Lewontin, the Alexander Agassiz Research Professor at Harvard, writes: “The scientists writing about the Genome Project explicitly reject an absolute genetic determinism, but they seem to be writing more to acknowledge theoretical possibilities than out of conviction. If we take seriously the proposition that the internal and external codetermine the organism, we cannot really believe that the sequence of the human genome is the grail that will reveal to us what it is to be human, that it will change our philosophical view of ourselves, that it will show how life works.”

Whatever future medical breakthroughs the Genome Project may or may not produce, it is already laying to rest the eugenic belief in distinctly separate races defined by fundamental genetic differences. Our species is such a recent evolutionary phenomenon that we haven’t had time to develop into distinct biological groups in any significant way. The genes responsible for our external differences of skin color and hair texture represent about .01 percent of each individual’s total genetic makeup. The bulk of the 30,000 or so genes of the human genome are proving to be strikingly alike. In the words of Dr. Eric Lander, a genome expert at the Whitehead Institute, in Cambridge, Massachusetts, “There is no scientific evidence to support substantial differences between groups, and the tremendous burden of proof goes to anyone who wants to assert those differences.”

Though humans will undoubtedly continue to be divided by culture and environment, it seems that when all is said and done, we really are one big family. Whether we’ll ever manage to be one big happy family remains to be seen.

—P.Q.