IN THE LAST two parts, we’ve looked at all the ways life on Earth, and especially humanity, have managed to survive hardships that ranged from meteorite strikes and megavolcanoes to the perils of migration and disease. Now we’ll turn to the stories of humans and other life-forms who have survived into the present day, using techniques that could serve us well as we make plans for a future world where our descendants can thrive. We’ll begin with the story of a group of humans, an ancient tribal people today called the Jews, who have retained a distinctive cultural identity for thousands of years. They’ve survived several deadly episodes of persecution in part by scattering and escaping in the face of adversity, rather than allowing themselves to be extinguished in the flames of war. In fact, this strategy of scattering is a crucial lesson taught to children during Passover, one of Judaism’s most important cultural rituals.
When I was the youngest kid at Passover gatherings, I was given the job of reading some questions that are a crucial part of the prayers. None of them made any sense to me, including the very first one: “Why is this night different from all other nights?” As I squirmed in my seat waiting for dinner, I hoped that the answers would explain why I had to eat such weird food, like parsley dipped in salt water and sweet apples mixed with eye-watering horseradish. After many years of grumpily contemplating why I had to eat things that symbolized the tears we shed during slavery, I figured out that Passover had nothing to do with dinner, and everything to do with memory. Passover is the one night every year when Jews retell the biblical story from Exodus about how the diaspora began. It’s become such an important ritual for Jews because the allegorical stories in Exodus mirror actual catastrophic events in Jewish history. This story of survival in the Bible became, in a sense, a template for survival in the real world.
But before we consider Jewish survival in recorded history, let’s recall the Passover story (apples and horseradish are optional). Thousands of years ago in ancient Egypt, the story goes, Jews lived as slaves under a cruel Pharaoh, making bricks for his pyramids and sorrowfully watching their families destroyed by backbreaking labor. Eventually a great leader came along, named Moses, and he begged the Pharaoh for his people’s freedom. When Pharaoh refused, he discovered that the single, incorporeal God of the Jews—so different from his people’s many half-animal gods—had some tricks up His sleeve. The God of the Jews sent ten plagues to devastate the Egyptian population, including crop-eating locusts, frogs falling from the sky, and a rain of blood (this always struck me as particularly awesome when I was a kid). In the worst of the plagues, God’s “angel of death” took the firstborn son from every house that wasn’t Jewish. Finally, the Pharaoh was persuaded. He told Moses to get his people out of the city, and the Jews spent one frantic day packing all their goods. They didn’t even have enough time to let their bread rise, which is why we symbolize this part of the story by eating a flatbread called matzo during Passover.
Apparently, at the last minute, the Pharaoh changed his mind about the whole deal and tried to send his soldiers after the fleeing Jews. That’s when Moses got superheroic, held out his hand, and parted the Red Sea. If you’ve ever seen Charlton Heston chewing the scenery in The Ten Commandments, you know what happened next. The Jews raced to the other side of the sea, hotly pursued by the Egyptian army. But once they’d reached the far shore, Moses let the waters smash back into their proper place, drowning the army and beginning the first chapter of the diaspora story.
For forty years, according to the Bible, the Jews wandered in the desert of what was then called Canaan, looking for a place to live. That’s when they became a diaspora people, a group far from their ancestral home and searching for a place to live where they wouldn’t be enslaved or worse. Later in the Bible, God leads the Jews to their “promised land,” eventually called Israel, which their children are destined to conquer. But the story of the book of Exodus ends with the Jews still in the desert, having won one battle but facing many more, unsure whether they’ll survive to find a home.
This ending is as significant as the structure of the story itself. It’s oddly realistic, leaving our main characters stranded in the middle of events whose outcome only their children will ever know. It suggests that when we struggle for a better life, we may never reap the benefits of that struggle ourselves. At the same time, the meat of the story is a powerful antidote to ancient tales glorifying war that were written during the same era as Exodus probably was. Stories about how cool it is to rip your enemies’ faces off appear elsewhere in the Bible (the books of Kings and Judges are complete bloodbaths), as well as in cuneiform tablets created by groups in the Assyrian empire and others. During a time in history when most nations celebrated military force and gory battles, the diaspora story in Exodus teaches us that there is great bravery in retreat. It is an act of tremendous strength to choose life and an uncertain future, rather than death in war. For the Jews who internalized this message, rather than the slaughter-is-nifty one, survival became a struggle that was often more difficult than death. But they lived. And so did their children, for generations that spanned millennia.
In modern parlance, the term “diaspora” refers to the geographical dispersion of people who are separated from their homeland. But, as political scientist William Safran explained in the first issue of the scholarly journal Diaspora, it can also refer to the diverse peoples who are the result of such a movement. Many groups have experienced a diaspora, including Africans outside Africa and Asians outside Asia, often due to some kind of major social upheaval. Today, these groups as well as Jews are commonly called diaspora peoples, even though many of them live in the same place that their families have for generations.
The word “diaspora” comes from ancient Greek, where it was first used to describe people who left their homelands to colonize distant regions. Gradually the term was applied to the Israelites of the era of the Babylonian exile, whose experiences were ironically the opposite of the original Greek meaning.
Though the rich geographical detail of the story in Exodus has led many to assume that it’s based on an actual historical event, archaeological excavations over the past few decades suggest that the story captures the spirit of the Israelites, but not their actual historical origins. UC Berkeley archaeologist Carol Redmount studies ancient Egyptian civilizations, and says there’s no evidence that the Jews or even their Asiatic ancestors were in Egypt during the time period described in Exodus—roughly during the reign of Rameses in the late second millennium BCE.
Instead, based on archaeological surveys of the region, it seems likely that the Jews during this time were a nomadic group whose members began to settle in small subsistence communities in the hills near Egypt at the height of the Bronze Age in the 1400s or 1300s BCE. Over the next several hundred years, these groups established many kingdoms, including a thriving northern region called Israel. But then in the eighth century BCE, Israel fell to the Assyrians and the formerly backwater southern kingdom of Judah rose to power. Judah’s biggest city, Jerusalem, once a hick town, became a thriving, walled metropolis hugging the base of the famous Temple Mount. It was also during this period that some archaeologists believe Jewish priests in Judah put the book of Exodus together from several sources.
Still, we don’t find archaeological evidence for a situation comparable to the one described in Exodus until the sixth century BCE. At that point, Judah had been a client state of Babylon for decades, and tensions between the two powers finally reached a breaking point. Judah revolted against the Babylonians and was completely crushed. In 587 BCE, the Babylonian king Nebuchadnezzar II led his troops into Jerusalem and destroyed it. Archaeologists have found sooty traces of a massive fire within the city’s walls from this era, along with countless arrowheads. The burning of the city sent many Jews into exile throughout the region, but within a few generations many returned to Jerusalem and assimilated into Babylonian society, adopting the local language, Aramaic, for writing. Indeed, in Jewish writings of the period, Judah is referred to by the Aramaic name Yehud. It’s also during this era that the nomadic hill people who created the nations of Israel and Judah started calling themselves Yehudim, or Jews.
One might argue that Jewish identity coalesced during a period when its nation was fragmented. And the Babylonian exile was just the first of many great fragmentations recorded in Jewish history. In the first century CE, Jews fled the Romans; in the fifteenth century, they raced to outrun representatives of the Spanish Inquisition; and still later, they abandoned large parts of Europe to escape the twentieth-century Holocaust. Passover has probably remained such an important ritual because it’s designed to remind Jews of our shared history as people who scatter in order to survive. To this day, we dwell in all the far-flung places where Jewish communities large and small continue to tell stories of a legendary time when we clung to life by running as far as we could, in as many directions as we could.
But is scattering really a good survival strategy outside of legends? If Jewish history is any guide, the answer is yes. Despite centuries of persecution and diaspora, there are people all over the world who call themselves Jews. And now we have scientific evidence that today’s Jews haven’t just inherited a cultural tradition. Some of us really do have biological ancestors who survived by wandering in the desert and beyond to find new homes. Population geneticists say there’s strong evidence that a group of Jews originating in ancient Rome over 2,500 years ago share identifiable genetic links with Jewish populations today from Spain, Syria, North Africa, Russia, and many other places. In other words, many Jews today owe their existence to people who scattered.
Geneticist Harry Ostrer has contributed to one of the world’s largest and longest-running genetic studies of Jewish people. An energetic and talkative man, he collaborates with colleagues and subjects across the globe from a slightly cluttered office at the Albert Einstein College of Medicine, surrounded by family pictures and lab equipment. Located in a quiet neighborhood in the Bronx, the college is practically in the backyard of some of the groups Ostrer studies, like Brooklyn’s Syrian Jewish community, as well as a few Iraqi Jewish enclaves in Queens. He’s done work with a large group of Turkish Jews in Seattle, too.
Studying these groups and others has given Ostrer a perspective on the results of diaspora, rather than the events leading up to it. One point he emphasized strongly was that diaspora is more often about staying rather than scattering. Jewish history can be characterized by long periods of settlement and assimilation into local cultures, punctuated by sudden shifts when many people abruptly fled to new lands, usually to escape persecution. As geneticist David Goldstein notes in his book Jacob’s Legacy: A Genetic View of Jewish History, some of the earliest historical records of the Jews come from sixth-century BCE cuneiform tablets, which describe the Babylonian conquest of Jerusalem. But the results of that diaspora are lost to history. The next great Jewish settlement took place in Rome, and the diaspora that resulted has genetic echoes all the way up into the twenty-first century. The Roman diaspora is the focus of Ostrer’s research.
There are extensive records of Jewish culture from the Roman empire during the first century CE. Many of these Jews were brought to Rome as slaves starting in the second century BCE, from Greece, Judea (the former southern kingdom of Judah), and many areas in the region. Over the next century, Jews assimilated into Roman culture and became one of the biggest and most powerful minority groups in the empire. Though we have no reliable source for how many Jews there were in Rome, we know from contemporary sources that Judaism was a highly visible religion. Politicians issued laws regulating the practice of Judaism, and many Jews became Roman citizens. Meanwhile, in the courts, commentators often complained of Jewish “disturbances”—probably referring to political unrest in response to constantly shifting Roman rules about Jewish taxation and social status.
Unlike today, Roman Jews expanded the ranks of their temples by actively proselytizing. They assimilated into Roman life, but Romans assimilated into Jewish traditions, too. It was a time of great cultural mixing that finally came to an end in the late first century CE, when Emperor Claudius ordered all Jews to be expelled from Rome. A few years later, some Jews in Jerusalem rebelled against the Roman control of their city and were defeated, while Roman Jews fled their homes to avoid death or worse. In the Bible, this period is referred to as the time of the Second Temple’s destruction because the Romans destroyed the house of worship on the Temple Mount just as the Babylonians had over 600 years before.
Though this diaspora survives in historical documents and biblical stories, Ostrer wanted to know if he could track down evidence of a direct genetic connection between the Jews who left ancient Rome and the Jews alive today. To find out, he had to get DNA samples from hundreds of Jews across the world, looking for genetic commonalities. “I went to Rome and did recruitment there,” Ostrer recalled. “That’s been a stable community for hundreds of years and perhaps dates back to the community that was there in classical antiquity.” He also got samples from Eastern European Jews as well as Jews in immigrant communities in the New York area. Anybody who could trace their Jewish ancestry back two generations to all four of their grandparents was eligible to participate.
Once he’d amassed his samples, Ostrer and his team had the beginnings of what they call the Jewish HapMap. “Hap” is short for “haplotype,” a term geneticists use to describe a set of unique genetic markers in the human genome. People who share haplotypes are more closely related to one another than people who don’t, and Ostrer wanted to know whether he could identify distinctly Jewish haplotypes. Over several years, the researchers at the Jewish HapMap Project scoured their data using a variety of statistical methods to compare both short and long strands of DNA from volunteers. They began to see patterns suggesting that people who had lived close together centuries ago still shared genetic similarities. Jews in Central Europe today share more genetically with Jews in the Middle East than a non-Jewish person living in Central Europe does with a non-Jewish person in the Middle East. And it’s all because those groups of contemporary Jews had ancestors from the same regions of Rome. Discoveries like this demonstrated that there are distinctive Jewish haplotypes that offer hints about where people’s ancestors settled in the diaspora.
Once they had enough data, Ostrer and his colleagues could actually create genetic maps tracking the spread of Jewish haplotypes out of ancient Rome and into the Middle East and Europe. Why were they able to isolate these haplotypes at all, when so much time had passed? It had to do with a change in Jewish culture after the Roman diaspora. Jews in ancient Rome were proselytizers—they converted many people and intermarried with non-Jews regularly. The Jews of that era would probably have shared haplotypes with their Jupiter-worshipping neighbors. But after their expulsion from Rome and the destruction of Jerusalem in the first century CE, Jews changed the structure of their communities radically. No longer were they permitted to proselytize and intermarry. To be considered truly Jewish, a child had to be born of a Jewish mother, establishing a rigorous matrilineal line. Without realizing it, the Jews of the first century created a culture that allowed their unique haplotypes to endure over the next 2,000 years.
Mapping the diaspora becomes more difficult when you add in the evidence of extensive assimilation and intermarriage taking place in Europe before the Inquisition. In countries like Spain, Jews enjoyed a social status comparable to the one they had once held in ancient Rome. They were prominent members of their cities, intermarried with non-Jews, and dramatically expanded their communities. But the tide turned in the fourteenth century, which saw the rise of political persecution of Spanish Jews. This culminated in the fifteenth century as the Spanish Inquisition spread outward into Portugal and Rome, and once again sent Jews running into their familiar diaspora pattern, pushing them deeper into Europe and the East. Still, they survived and even retained some of their haplotypic particularities. A group of Portuguese anthropologists recently discovered a small group of Jews living in the mountains of Portugal whose ancestors had apparently fled there and masqueraded as Catholics to escape the Inquisition.
Despite what he and other geneticists have discovered, Ostrer is wary of saying too much about the genetic basis for Jewish identity. This is an area of inquiry that is still evolving rapidly, and he’s quite willing to admit that some of his conclusions are simply “a guesstimate.” There is no single haplotype that unites all Jews—instead, he and his team found four distinct haplotypes identified with different Jewish diaspora groups. There will never be a genetic “Jew or Not” test. All that Ostrer’s work reveals is that a genetically identifiable “Jewish people” survived the diaspora. We now have both historical and genetic evidence that scattering and hiding out during times of upheaval is a good way to ensure that your progeny will survive—even for dozens of generations.
Toward the end of my conversation with Ostrer, we started talking about Jews today. We’re in the midst of another period of Jewish assimilation and migration, he said, making a sweeping gesture with his hands as if to encompass all of New York, or possibly the world. In the wake of nineteenth-century pogroms and the twentieth-century Holocaust, many Jews were forced to scatter to new areas. And some, like Reform Jews in the United States, have started converting people to Judaism again. The result of all this movement and intermixing is a Jew like me. My mother was a Methodist who converted to Judaism before she married my Jewish father. I was raised Jewish, but who knows what kind of haplotype I have? More to the point, when we’re talking about the survival of a group over centuries, does it really matter whether I’m culturally Jewish or genetically Jewish or somewhere in between? After hundreds of years of diaspora, aren’t all survivors a little bit hybrid?
This is exactly the question that people from many diaspora groups have raised over the past half century. Perhaps nowhere is the answer to it more beautifully expressed than in the book The Black Atlantic: Modernity and Double-Consciousness, by Guyanese-British scholar Paul Gilroy. While researching the often fragmented histories of blacks in England, Gilroy realized that he should reframe black identity as a hybrid experience that combines many cultures. To describe the origin of this experience, he called on the idea of a “black Atlantic,” the geographical region where African slaves were scattered in a forced diaspora across Europe and the Americas. Instead of having a single point of origin, like the lands around Jerusalem, Gilroy’s diaspora has many origins. And its survivors are genetic and cultural hybrids. But that doesn’t mean African identities have been extinguished in people outside Africa today. It has survived in a multitude of ways, though some of them might be unrecognizable to communities who lived in Africa half a millennium ago.
As Ostrer put it, diaspora is about where you come from, but it is also about where you end up. Our journeys change us radically, but when we settle down again there is a continuity, a shared history that holds us together. Jews and Africans are not unique in this respect—many groups have maintained a sense of community through times of hardship and separation. Recent human history teaches us that your group has a better chance of surviving in the long term if you’re willing to divide into groups and go your separate ways to safety. But that doesn’t mean the past is lost. What makes a book like The Black Atlantic so important is Gilroy’s powerful assertion that even if your group is unwillingly torn apart and assimilated into other cultures, your progeny will remember where they came from even hundreds of years from now.
The Passover ritual makes a similar assertion. It is a celebration of identity forged in diaspora, and a reminder that survival often means finding a new home. The difficult part, as we face an uncertain future, is how to understand the meaning of “a new home.” We may have to look very far afield to get our answers. In fact, one of the greatest stories of survival through adaptation does not come from humans at all. It comes from the humble blue-green algae, whose incredible history may also show us one possible path into the future.