But did these people have reason to believe they were somehow Native? I asked.
“A lot of it is lore. They’ve had all this history over their lifetime that says their great-grandmother was a Cherokee Indian princess, yet we show no Native American in their DNA sample. But it may have gone somewhere else; their brother may have it, or their cousin. But ultimately, if it’s not there they get furious.”
A Cherokee princess. Stephen’s story sounded more like a rural legend the more Lou talked. She told me about a fellow who had called the day before to complain that he was banking on Native scholarship funds to put his kids through college. She told me about tribes that have people storming their doors claiming to be 16 percent Native American, and that many tribes simply won’t accept DNA as evidence.
And really, I thought, why would they? To be Native American, or to be anything for that matter, is a question of culture and tradition, not biology. Even if we had a pile of genetic markers in common with First Nations people, it did no more to cement our identity as being Native than hanging dream catchers on our bedposts or seeing my father’s nose in a hockey team’s logo.
I assured Lou that I had no interest in exploiting our newfound Native ancestry, and that I had quite the opposite problem—it was totally unexpected. The test had turned up a percentage of Native markers in my father, my brother and me that was so high it had left us bewildered. We believed we hailed from parts of Europe and India, and possibly China, and this was the very last thing we had imagined.
“What was your percentage?” Lou asked.
“For my father, it was 25 percent; for me, 22.”
“Wow,” she said, “that’s pretty high.”
If Lou “I’ve Heard It All” Charlton thought that sounded like a whole lot of Native, then I figured our result warranted further explanation. I asked if there was a way to find out in which tribes those markers had first been identified, and whether they were also common in people from other parts of the world.
Lou said she couldn’t be sure but that it was not uncommon to find Native ancestry in southern Europeans, herself included. “It was my biggest surprise too,” she confessed, “and I wasn’t even that high, maybe about 10 percent.” Her Italian ancestors had come through Ellis Island in 1900; they didn’t speak a word of English and “probably didn’t even know what an Indian was.” Even Tony Frudakis, who is of Greek descent, she said, discovered he had “a bunch of Native American in him too.”
For weeks the words “call Frudakis” appeared on my to-do list. But DNAPrint’s chief scientific officer was hard to reach. In the meantime I tracked down Ripan Mahli, the young geneticist who had helped to design the Native ancestry component of the company’s test. In fact he’d recently left DNAPrint to start his own firm, specializing in Native ancestry testing, and he agreed it was a tricky business. Basically any reading below 12 percent could be inaccurate, or not strictly reflective of Native American ancestry, depending on what other geographic areas were mixed into a person’s origins. People from southern Europe all the way to Japan can carry many of the same mutations that can be found in Native Americans. That doesn’t make the mutations “Native,” but rather more Central Asian, reflecting the genes of the ancient Asian population that migrated from that part of the globe and populated other regions: the Americas, East Asia, South Asia and Oceania, in the South Pacific (one theory has it that Natives arrived in the Americas in successive waves from Oceania).
Ripan forwarded me an academic paper he had co-authored. It noted that for someone with Native ancestry below 3 percent, it might not be detected by the test (a statistic I promptly offered to Stephen, like a pillow). Neither could any specific tribe be identified by genes alone; through the millennia, tribes had intermarried, adopted, split and merged, and in the process traded genes like they had horses.
Ripan said the markers used in the test had first been identified in samples taken from Native and Mayan populations in the south-western United States, but other studies show they are generally representative of the various Native groups in North America. The most compelling detail he shared was that these markers are particularly difficult to distinguish in people who also have East Asian ancestry. Someone of East Asian descent has to have a Native American ancestry reading of at least 13 percent to conclude that she actually has Native ancestry, he said, explaining that East and Central Asians have many mutations in common.
When I told him I had South Asian roots, as well as a high reading of East Asian and Native ancestry, Ripan suggested the combination might not reflect any input from the Americas at all. In all likelihood, in our case it was all Asia, all the time.
Over time my father became less captivated by the prospect of Native ancestry than with the idea that he had somehow passed down to me all his Native ancestral markers. In fact it led to the development of his “super-sperm theory,” which he shared over dinner one night.
“I wonder if the mood, the emotional state of the parents, has some bearing on what happens at conception,” he offered gingerly.
“What do you mean?” I asked.
“At the time you were conceived in England, I was at the peak of my career. I was managing a team of 250 men! We were putting in a large proposal to build a power plant in the Midlands, and there was a deadline to meet. I was a bit of a tyrant. I kept the men there all night. Remember, Tweet?” he asked my mother. “You had to bring me breakfast and my toothbrush. When they called and said we had won the bid, well, I was elated!”
“So then what?” I asked. “You thrust your chromosomes upon me?”
“I’m just saying, you wonder if that has an effect on the way a child is conceived,” Dad said. “I was in a domineering state and somehow that affected your DNA.”
My mother rolled her eyes and I laughed, dismissing my father’s theory as a testosterone-clouded perspective. But just a few months later, Stephen Scherer, a leading geneticist at the University of Toronto, found the first evidence that the way parents’ genes divide when making a new child was not necessarily in a fifty-fifty split. Working with researchers from Harvard, the Sanger Institute in London and the University of Tokyo, his team discovered that a child can inherit more genes from one parent than the other. Ever since Gregor Mendel set down the laws of genetic inheritance 150 years ago, people have assumed that each person inherits two copies of every gene, one from each parent, making each child equal parts mother and father. But Scherer and his group found that people do not necessarily have the same number of genes, that one person can inherit as many as ten copies of a gene, several from one parent and none from the other, or even receive no copies at all of a gene and still appear to be perfectly healthy.
Scherer told me that scientists were not certain how one parent’s genes might come to dominate the other’s, which of course made me wonder if my father was on to something with his super-sperm theory. After all, men make sperm every few days, and perhaps the same hormones sloshing around the male body that affect mood might also affect their sperm. Next thing you know, you’re a quarter Native. Scherer laughed when I asked him about it. “Who knows?” he said.
It is hard to overstate the impact of Scherer’s discovery, since it turned the basic idea of genetics on its head. But it was also a powerful reminder that genetics was still a very young science—one that could be skewed by naïve definitions of normal or even warped by the words used to describe it.
When I finally reached Frudakis, that’s how he explained the confusion over our Native ancestry result—semantics. The Florida company had pegged its markers as being Native American to appeal to the American market, he told me. But it was accurate to consider them Central Asian markers, he said, that had been carried to different regions by those who migrated from that part of the globe long ago—into the Americas, into East Asia, South Asia and even southern Europe—finding their way into today’s Greeks, Italians and Turks. “We may do ourselves a favour and change the name of this ancestry [component] in
the test,” he said, since apparently I wasn’t the only one baffled by it.
But no matter what he called it, I had to question whether the markers involved could even be considered “ancestrally informative.” Connecting a relatively small group of mutations found in many different populations to a single ancestral group was bound to breed confusion. Calling our mutations Native seemed to be like calling us Arabs because we have swarthy skin. The only information it seemed to provide was that all these far-flung, diverse groups—Turks and Mayans, Italians and Cherokees, Indians of India and of the Americas—share a few strands of common heritage.
But just as Nana Bridget had done with her channelling, people could take from this DNA result whatever they wanted to believe. Stephen contented himself with the idea that the test was inadequate to find his Native connection, and I ignored it for suggesting that somehow we had one. If it had personal value, it was the proof that our DNA is indeed as mixed as I had always heard it would be.
Our heritage spans at least three continents. But scanning the whole genome to try to learn our history was like tossing a loose net into a sea of nameless ancestors when it was the juggler and the Captain I wanted most to catch. For that I had to cast my line narrowly, down to the tiny slivers of a chromosome that each patriarch had left behind.
4
A MOLECULE OF MEMORY
The first time I talked to my parents about the Y chromosome, it unfolded like the old “Who’s on First?” Abbott and Costello skit. It was late in 2005, before the first DNA results from Florida had arrived, and I was at their house laying out plans for the next round of testing, telling them it was a terrific coincidence that the deepest mysteries on both sides of our family involved grandfathers. Being men, they both carried Y chromosomes and passed them down to their male children. From what I’d read, the most powerful genetic tool in genealogy research is the Y chromosome.
“The what?” my mother said.
Jade, who was about two then, was sitting on the kitchen floor bashing Tupperware with a wooden spoon.
“The Y,” I said.
“Why what?”
I had a vague sense that I had become the family eccentric. But I continued, while Jade drummed, explaining why the Y chromosome seemed the most promising way to learn where John Abraham and Frederick Crooks had actually come from, and how it may even lead us to details of their histories.
The Y was the one gift they had unwittingly bequeathed each of their male descendants. Papa Freddie had inherited the captain’s Y chromosome and passed it on to my mother’s brothers. Papa Albert had inherited the juggler’s Y and passed it to my father.
“It is only the men who pass down the Y, isn’t it?” my mother said.
Yes, it’s one of the two sex chromosomes, I told her. Women have a pair of Xs and men have an X from their mother and a Y from their father, and their father’s father, and their father’s father’s father, and on it goes. If sperm carrying an X chromosome fertilizes an egg, the baby will be a girl. But if the sperm carries a Y, the chromosome flicks a molecular switch and testicles sprout.
“Look at that,” my mother said. “Henry VIII beheaded all those poor wives and it was his fault.”
Not to defend the sixteenth-century uxoricidal monarch, but it wasn’t until the seventeenth century that a Dutch scientist put his own semen under the microscope and discovered sperm. And it was another two hundred years after that, at the dawn of the twentieth century, that the male’s Y chromosome was first identified—in a sublime twist, by a woman, the American scientist Nettie Stevens. Even then the Y was largely overlooked for much of the twentieth century, especially as a guide to trace paternal ancestry. Studies that had unravelled stretches of its code from a few dozen men found very few differences between them, leaving the impression that if you’d seen one Y, you’d seen ’em all. Instead, scientists were reconstructing the history of human populations with research on mitochondrial DNA, a special form of genetic information that only women pass down to their children, male or female. The package passed down by men to their sons was largely dismissed as a genetic wasteland.
Under powerful microscopes, most chromosomes look like plump, fuzzy caterpillars. The Y, the smallest chromosome in the human genome, looks more like a slug. In her landmark paper in 1905, Nettie Stevens referred to it as an “accessory,” as if the molecule of manhood were a clutch purse. But next to the elephantine proportions of, say, human chromosome 1—which boasts some 2,500 genes and the imposing swagger of 246 million base pairs—or its opposite chromosome, the full-bodied X, with more than a thousand genes doing thousands of jobs, the Y is a 58-million-base-pair pipsqueak with fewer than two hundred genes and, for the most part, a one-track mind. Making sperm and testicles is its chief job.
The only story the Y seemed to tell was the sad and lonely tale of the chromosome nature forgot. Once upon a time it was as large and robust as the grande dame that is the X, delivering malehood to stags, rams, jacks, bulls, boars, tomcats, mane-frilled lions and men. But in the 300 million years since it first appeared in the genome, the Y has suffered mightily. Every other chromosome has a chance to refresh itself before it builds the next generation, by swapping genes and correcting mutations as it bends and unwinds with its matching partner. But the Y has no matching partner; it trades only bits and bobs with the X, at its tips. With little chance for self-improvement, mistakes have piled up. Most of the Y chromosome’s original genes have been shed or rendered completely useless by mutations. Even the genomic carcasses of long-dead viruses hide in its code.
The human Y, however, has come up with ingenious ways to preserve itself, madly copying its own code like a hall of mirrors, evolving so quickly that it now looks nothing like its counterpart in, say, the chimp. Still, the fate of the male chromosome has prompted a flurry of studies, essays and entire books on the genetic future of men.
Yet it was the not the future but the past that drew a new crop of geneticists to this embattled chromosome late in the twentieth century, pursuing the idea that a secret history might be written in the mutations of its jumbled code. Generally mutations that pop up in genes tend to cause malfunctions or disease, and they don’t stick around long in a population. But mutations in regions that have no genes—stretches of code nicknamed “junk DNA” before anyone realized their crucial value in regulating genes—can have a much longer shelf life. And the Y is a treasure trove of junk. It has more junk than genes: 98 percent of it is nothing but junk. It’s the attic of the genome, the garage, the flea market. (The Human Genome Project did not even try to decode the entire Y chromosome, because of all the junk it carts around.) Yet these are some of the very characteristics that happen to make the Y an invaluable tool for tracing family roots.
Precisely because most of the chromosome does not recombine before a new sperm cell is made, the only changes or mutations it accumulates are the ones that spring up randomly in the man who carries it, and subsequently in the males who inherit it from him. As the technology to sequence DNA improved, so did the ability of scientists to spot those mutations and read them as the genetic signature of a male lineage. By the nineties, studies had emerged to indicate that every man’s Y chromosome does indeed carry a unique set of mutations corresponding to certain parts of the world. Men from Africa have distinct mutations on their Ys that are different from the markers on the Y chromosomes of men from China or northern Europe or southern Europe.
The more unique mutations researchers uncovered in different populations, the more they came to see the Y as a living archive. It might encode not only an ancestral record of the world’s men but the paternal heritage of any one man, passed down to him through the ages in a chain linking fathers to sons, much like a surname. In 1994 someone decided to put that hypothesis to the test.
That year, on a Saturday morning at a synagogue in north Toronto, just half an hour from my parents’ house, Karl Skorecki had an epiphany. Skorecki was a researcher and kidney specialist at Toronto General
Hospital at the time, and he was saying prayers and waiting to be called to read from the Torah. He was accustomed to being one of the first called to read, since he belongs to the caste of high priests in Judaism known as kohanim. The term is plural for kohen, the family name of those said to be direct descendants of Aaron HaKohen, the brother of Moses, a birthright that carries certain responsibilities to lead ceremonies of worship. But that day it was a kohen visiting from North Africa who was called first, and the fair-skinned, light-eyed Skorecki found himself staring at the man, taking in his swarthy complexion and distinctive features and thinking, He is from North Africa, I am from eastern Europe, and we look nothing alike … yet we are both of us kohanim.
Skorecki looked around at the other kohen men in the synagogue and noticed that, physically, they all looked different—in stature, in skin colour, in facial features. Nothing about their appearance suggested a common ancestry, yet apparently they had one. They all shared the same family traditions of spiritual leadership, the same rites and the same knowledge required to perform sacred duties at temple, as the teachings hold, by way of their mutual connection to a forefather who lived 3,300 years ago. Was there any genetic evidence of this bloodline legacy, Skorecki wondered. Did kohanim share a common biological marker as well as a sacred culture?
He realized instantly that any such marker would likely have been lost in “all the mixing and matching that goes into DNA through the generations.” But then it struck him that the Y chromosome remains more or less unchanged generation after generation, passed down through centuries—like a family secret, he thought—so that the Y chromosome of a man alive today should be essentially the same Y as that of his ancient male ancestors.
The Juggler's Children Page 6
