* Although rare in blacks and Asians, cystic fibrosis is a common lethal genetic disease in those of northern European ancestry. Whites are more likely to get multiple sclerosis than all other population groups, while blacks and some Mediterranean populations are susceptible to sickle cell anemia. Some 2 million whites worldwide now carry copies of a mutant gene that makes them immune to human immunodeficiency virus (HIV) infection. Rare mutations may help insulate some southern Asians from severe acute respiratory syndrome (SARS). The presence of one gene is a potent risk factor of Alzheimer’s for whites, but not for blacks. The variant of one gene may explain why black women have twice the risk of premature delivery than women of European ancestry. Those of African ancestry are more susceptible to heart disease and are 50 percent more likely than whites to die of colorectal cancer, even if they receive the same treatment. Irish and others of Celtic ancestry are disproportionately victimized by Dupuytren’s disease, also known as claw hand. One mutation accounts for the sensitivity of the Japanese to alcohol, while another gene variant carried by at least a fifth of all Semites helps them break down liquor in the bloodstream, protecting them against alcoholism.
Although geneticists generally avoid using the term “racial” to characterize differences that show up more in one population than others, ancestry matters. Because modern humans move around and fool around far more expeditiously than their ancient ancestors, modern “races” and ethnic groups are fuzzy at the edges and overlapping. As a rule, the more historically isolated a population—because of geographical or cultural barriers—the more distinct its genetic makeup.
* The number of Jews worldwide is thought to be about 13 million, although estimates are invariably hazy because of the complex notion of Jewish identity. The total has been dropping by 300,000 each year. Approximately 10 million Jews are Ashkenazim, a word derived from the Hebrew word for “German,” which suggests their recent European roots. (About 90 percent of the approximately 5.5 million Jews in the United States are Ashkenazim.) The remainder are mostly Sephardim (from the Hebrew word “Sefarad,” meaning “Spain”), who trace their ancestry to Iberia or North Africa, the center of diaspora Jewry until the medieval inquisitions; and indigenous Jews from the Middle East known as Orientals, most of whom now live in Israel. Endemic intermarriage and a low birthrate will continue to slice into the marrow of Judaism. With the Jewish fertility rate below the level necessary to replace the current population, in just a few generations, two out of every three Jews could disappear.
* Prebiblical pagans were satisfied to find purpose in the sun, moon, the cycle of the seasons—the power of nature. Consider how appalled they must have been when they encountered these wandering Semites, who proposed that meaning could be found in something as insubstantial as One God. It was a crazy enough idea to change the course of history.