"I was told that my family story in America goes back to the Mayflower," said University of Washington geneticist Mary-Claire King. King looks every ounce the Protestant blueblood that she once fully believed she was. But her genes tell a more complex and fascinating story. She is living proof of the shared Israelite ancestry of Jews, Christians and Muslims, while her research holds the key to the mystery of "ethnic diseases."
In 1990, after years of paintstaking effort, King identified a cancer perpetrator that she named Breast Cancer One, written as BRCA1. The discovery heralded a new age of DNA research--focusing on diseases that can often afflict one ethnic group or population more than another. In the case of two breast and ovarian cancer mutations on BRCA1 and a third on BRCA2, the targeted population, almost exclusively, is Jews. About one in 40 Jews carries one of these anomalies, which can raise the lifetime risk of those cancers to 80 percent.
It threatens to resurrect the discredited notion that Jews are a "race"--a term geneticists no longer use.
King's research is very personal to me, as my sister contracted breast cancer a few years ago. Her cancer was linked to BRCA2 mutation. Three family members, including my mother, died of similar cancers when I was a teenager. I was tested and found to carry the mutation. It's difficult to trace this wayward gene as my family tree disappears into the fog of the 19th century diaspora. The only thing scientists can say for certain is that, like some 40-odd other genetic disorders that are common among Jews, this cancer is a tragic marker of shared ancestry. It was my sister's illness and concerns about my 9-year-old daughter--the product of a mixed marriage, she has a 50/50 chance of being a carrier--that led to the writing of my book, "Abraham's Children: Race, Identity, and the DNA of the Chosen People," which features King's groundbreaking studies.
Most geneticists believe that the three mutations trace to Jews who lived 1,000 or more years ago when European Jewry numbered fewer than 25,000 people. As Ashkenazi Jews passed through a "population bottleneck" and their numbers began to explode, those genes spread quickly, from Jewish shtetl to Jewish shtetl. They became, along with cultural signatures such as devotion to the Talmud, markers of being Jewish.
It's hard to understate the thorniness of discussing "Jewish genes," as the BRCA mutations are often called. It threatens to resurrect the discredited notion that Jews are a "race"--a term geneticists no longer use.
Since the founding of Ashkenazi Jewry until recent decades, despite being scattered to winds of the world, the rate of nonJewish lineages that have slipped into the Jewish gene pool, per generation, is estimated at 0.5 percent, which ensured that "Jewish genes"--disease mutations and perhaps even genetic mistakes linked to other characteristics such as verbal facility--stayed within the insular but extended Jewish community.
There has been far too much intermixing throughout history, and far too many horrific abuses based on facile racial rankings, to justify resurrecting the pre-genetic notion of "race." Humans move around and fool around. King's unusual family history stands as a prime example. While still in college, she discovered, by accident, that her mother had buried a major trunk of the family genealogical tree. Her grandfather, her mother's father, whom she had known as Louis Gates, was actually born with the surname Cohen, which means priest in Hebrew. Cohen was, by Jewish oral tradition a descendant of the first priest, Aaron, Moses' brother. Researchers in the mid-1990s discovered that more than 50 percent of self-proclaimed Cohanim (priests) have genetic markers that go back 3,500 years to a single male ancestor--possibly the biblical Aaron. It was an explosive finding, which helped usher in the era of genetic genealogy. As for Louis Cohen, he did not practice Judaism and raised his family as Christians. After the family ran an anti-Semitic gauntlet in their hometown of Tulsa, King's mother, Clarice, changed the family name to Gates, and vowed never to disclose her Israelite ancestry to her children, who were raised Methodist.
DNA is at once an atlas and time machine that can transport us to biblical times, awakening us to our family stories, the shared roots of civilization, and the promise of designer therapies.
But the human genome also presents surprises that are challenging the cherished notion that there are no significant differences between ethnic or racial groups. The great paradox of human biodiversity research is that the only way to understand how similar humans are is to learn how we differ.
Jon Entine is an adjunct fellow at AEI.