The Sports Gene: Inside the Science of Extraordinary Athletic Performance

by David Epstein

  But when hematologist Eeva Juvonen examined Eero’s bone marrow cells in the lab, she saw something astonishing. In order to test whether his bone marrow cells—which produce red blood cells—were particularly sensitive to EPO, the research protocol was to add EPO to a cell sample and track red blood cell production. Eero’s bone marrow cells began the process of creating red blood cells before Juvonen could even stimulate them with EPO. Whatever tiny speck of EPO that was already in the sample was enough to keep the red cell factories humming. So it was clear that Eero’s body heeded the call of even trace quantities of EPO with extraordinary vigor. Illuminating the reason why would require more members of the Mäntyranta clan.

  •

  Albert de la Chapelle identifies himself as a gene hunter. He is exceedingly good at tracking his prey. He is the geneticist who argued on behalf of María José Martínez-Patiño when she was barred from competing as a woman. These days he spends his time at Ohio State University training his sights on the genes that predispose people to the most deadly cancers ever known, like acute myeloid leukemia, which interferes with blood cell production and can put a previously healthy patient in the ground in a matter of weeks.

  De la Chapelle spent most of his career at the University of Helsinki, hunting gene mutations that cause diseases that show up in Finland far more often than in the rest of the world. These diseases come from so-called founder mutations, meaning that a mutation arose in a member of a small group and spread through that population as it grew. De la Chapelle was part of a team that clarified the genetic basis of more than twenty diseases—multiple forms of epilepsies and dwarfisms among them—that are endemic to Finland. (And sometimes to Minnesota, a state heavy with residents of Finnish ancestry.)

  Not long after Eero Mäntyranta’s blood was examined in the lab, de la Chapelle made a trip to Lankojärvi to meet a group of forty Mäntyrantas who had assembled at Eero’s house to talk with the researchers who were now studying their blood. It was winter, and de la Chapelle remembers marveling at the noontime sun as it kissed the surface of the lake.

  After a lunch of fresh reindeer prepared by Rakel, de la Chapelle set to mingling in the living room. “I was sitting there on the couch with these three elderly ladies,” de la Chapelle recalls, “and I already knew two had the condition and one did not. And they went over their health with me and it was the one without the condition that had all the health problems and the two with it were quite healthy and were unaware of anything at all being different with them.”

  Even if not for their slightly darker complexions, de la Chapelle would have known that the two healthy women had the blood condition. He had already been through their genomes.

  In all, ninety-seven Mäntyrantas were examined, twenty-nine of whom had remarkably high hemoglobin, along with slightly ruddier complexions than the average Finn. Unlike the initial study of Eero, this examination went more than blood deep. De la Chapelle probed all the way down to a particular gene on the nineteenth chromosome, the EPOR, or erythropoietin receptor gene.

  This particular gene tells the body how to build the EPO receptor, a molecule that sits atop bone marrow cells awaiting the EPO hormone. If the EPO receptor is a keyhole, it is one made specifically to accept only the key that is the EPO hormone. Once the key is in the lock, the production of red blood cells proceeds. The receptor signals a bone marrow cell to start the process of creating a red blood cell that contains hemoglobin.

  Of the 7,138 pairs of bases that make up the EPO receptor gene, there was a single base that was different in the twenty-nine family members who had unusually elevated hemoglobin levels. Each family member, like every human being, had two copies of the EPOR gene. But at position 6,002 in only one copy of each affected family member’s two EPOR genes, there was an adenine molecule instead of a guanine molecule. A minuscule alteration, but the impact was immense.

  Instead of adding information for the cellular machinery to continue to build the EPO receptor, the spelling change constituted a “stop codon,” the genetic equivalent of a period at the end of the last sentence of a chapter. A stop codon essentially tells RNA—ribonucleic acid, the molecule that reads DNA code so that it can be translated into action—that the instructions are finished. Move along, nothing more to read here, it says. So instead of coding for the amino acid tryptophan, as that section of the EPOR gene normally would have, the Mäntyranta family mutation caused the receptor simply to stop being built with over 15 percent of its construction unfinished. The unfinished portion in the affected Mäntyranta family members happens to be a segment of the receptor in the interior of the bone marrow cell. The piece of the receptor on the exterior of the cell awaits the EPO key, while the interior portion modulates the subsequent response, acting like a brake to halt hemoglobin production. In the affected Mäntyrantas, who are missing the brake, the production of red blood cells runs amok.

  Fortunately for the family, the overproduction of red blood cells did not lead to ill health. Save for the slightly dark complexion, family members had no outward signs of abnormality and generally discovered their condition by accident during routine checkups.

  The Mäntyranta EPOR gene finding was a major discovery in the early 1990s. The high hemoglobin condition in the Mäntyrantas was passed down through the family in an autosomal dominant fashion, meaning that only a single copy of the mutant gene was required for a family member to have the condition. Other dominantly inherited gene mutations had been discovered before that study, but they were generally tied to serious illnesses.

  In the papers they published in 1991 and 1993, the researchers noted that Mäntyrantas who carried the family EPOR mutation had long lives. They had found, it seemed, a mutation beneficial for an athlete and otherwise of little consequence. De la Chapelle says, though, that he could never convince Eero himself that the EPOR mutation aided him in his Olympic quest. “He kept saying that it was not his bodily strength,” de la Chapelle says, “but his determination and psyche.”

  •

  Since I came all the way from Brooklyn to meet him, Eero is eager to tell me about his visit to New York City after the 1960 Winter Games. “Scary” is how he describes his first impression of the morass of Cadillacs, streetlights, and asphalt.

  He has also laid out for me some of his most prized medals, the seven from the Olympics, and a medal of honor that the government normally reserves for military heroes. As they have for polar night, the Finns have an untranslatable word, sisu, that roughly means strength of passion, or calm determination in the face of obstacles. The Finnish government determined that Eero was the embodiment of sisu.

  Iiris, wearing shoulder-length blond hair and black-rimmed glasses, translates a story from her childhood about the aftermath of the 1964 Olympics, when the local electric company paid for Eero to return home in a helicopter. It landed atop the ice covering the lake amid hundreds of revelers who had gathered to celebrate. Iiris was a little girl, and remembers running excitedly toward the helicopter. At first, Eero enjoyed the attention, and it afforded him a job working for the local government teaching physical education to children. But it quickly became a burden.

  Through the mid-1960s, reporters would show up unannounced at Eero’s door asking him to “tell me a story, but not what you tell others,” Eero says through Iiris’s translation. Before competitions, tourists from southern Finland would drop by asking to see medals and to take pictures, requests that Eero and Rakel felt obliged to honor. For Eero, skiing had always been more about winning and getting a better job than an intrinsic love of the activity, so the unwanted attention was enough to push him to retire from ski racing following the 1968 Olympics, at the age of thirty.

  At the behest of a Finnish celebrity magazine, he made a brief comeback before the 1972 Winter Olympics in Sapporo, Japan. He had not skied a stride, or exercised at all, for three years, and he was well above his racing weight. The magazine promised to pay Eero’s
training expenses so that he could take a break from work so long as he gave the publication access to document his comeback. Eero returned to the trails just six months prior to the Olympics but made the team and finished nineteenth in the 30K race in Japan before going back into retirement, this time for good.

  Toward the end of my visit, we all take spots on couches and chairs in the living room, flanked by paintings of winter landscapes. Eero points out a series of sepia photographs hanging on the wall. They are of his ancestors. There is swarthy-skinned Isak, in a vest and newsboy cap, reclining on the ground of a forest clearing and enjoying a meal with Johanna, her head wrapped in a light-colored scarf. And above that is a picture of Eero’s parents, Juho and Tynne, sitting on wooden chairs in a patch of cleared land with several of their children.

  Isak and Juho died before de la Chapelle ever started probing the family genome, but enough Mäntyrantas were tested that he was able to create a genetic family tree and deduce that they had the EPOR mutation. Juho’s two brothers, Leevi and Eemil, also carried the mutation.

  But it will soon come to an end down Eero’s line. His son Harri had it and showed promise as a youth cross-country skier, but Harri died as a young man of an illness that had no relation to the EPOR mutation. Iiris does not have it, and of Eero’s remaining two children, fraternal twins Minna and Vesa, only Minna has it, but her only son does not.

  When I ask Eero whether he was relieved that the University of Helsinki doctors lifted the suspicion of blood doping from his victories, he says yes, but that he disagrees with the suggestion that the mutation gave him an advantage. Eero’s feeling is that the increased viscosity of his red-cell-loaded blood would have hampered his blood circulation, thus balancing any performance benefits. De la Chapelle disagrees staunchly. “It’s an advantage, there’s no question,” he told me, noting that Eero’s hemoglobin levels were the highest he has ever seen. “If the blood didn’t circulate well, that would be a pretty serious situation and you would know.”

  In recent years, Eero has had several bouts of pneumonia that his doctors think could be related to his thick blood, so he is now on blood-thinning medication. Iiris adds that the redness of his skin is also a recent development. During his competitive days, Eero showed no ill effects of his EPOR mutation, and other Mäntyrantas with the mutation have remained healthy into old age.

  While the extensive scientific documentation of the Mäntyranta family’s mutation is unique in sports, there have certainly been other successful athletes with preternaturally high hemoglobin levels. Endurance sports like cross-country skiing and cycling have set up systems whereby an athlete with abnormally high hemoglobin or red blood cell levels can earn a medical exemption to compete if that athlete can prove that his hemoglobin is naturally elevated. A number of athletes have been given such exemptions, and have gone on to great success.

  Italian cyclist Damiano Cunego was granted a medical exemption by the International Cycling Union and at twenty-three years of age became the youngest road cyclist ever to be ranked number one in the world. Frode Estil, a Norwegian cross-country skier who was given an exemption by the International Ski Federation, won two golds and one silver medal at the 2002 Winter Olympics in Salt Lake City. Neither of these men had hemoglobin levels as high as Eero’s—the normal range for men is 14 to 17 grams of hemoglobin per deciliter of blood, and Eero was high even compared with his own family members, consistently over 20 and as high as 23—but Cunego and Estil nonetheless had elevated levels that they could prove were natural and that were higher than those of their teammates and competitors who trained in similar manners.

  Like the naturally fit six from the York University study, there was just something innately different about them.

  •

  With the three-hour drive back to Luleå in mind, Iiris tells Eero and Rakel that she will see them soon for Christmas, and tells me that we should hit the road.

  As we are getting ready to leave, I suddenly chide myself for nearly forgetting to ask an obvious question. When I was told that the EPOR mutation will not continue down Eero’s direct line of descendants, I was disappointed that there would be no way to see whether it might push younger Mäntyrantas to athletic success. But from de la Chapelle’s family tree I know that there are extended family members who have the mutation.

  “Do Eero’s siblings have the mutation?” I ask Iiris.

  One of them does, she tells me. His sister Aune, and two of Aune’s children have the mutation, her son Pertti and her daughter Elli.

  And did they ski? I ask.

  They did, she tells me.

  And were they any good?

  Elli was twice a world junior champion in the 3×5K relay in 1970 and ’71. And Pertti, competing at the site of his uncle’s most famous triumphs, won an Olympic gold medal in the 4×10K relay in 1976 at the Innsbruck Winter Games. In 1980 he added a bronze at the Lake Placid Games.

  No one else in the family races.

  EPILOGUE

  The Perfect Athlete

  Eero Mäntyranta’s life story is a paragon of a 10,000-hours tale.

  Mäntyranta grew up in poverty and had to ski across a frozen lake to get to and from school each day. As a young adult, he took up serious skiing as a way to improve his life station—to land a job as a border patrolman and escape the danger and drudgery of forest work. The faintest taste of success was all Mäntyranta needed to embark on the furious training that forged one of the greatest Olympic athletes of a generation. Who would deny his hard work or the lonely suffering he endured on algid winter nights? Swap skis for feet and the Arctic forest for the Rift Valley and Mäntyranta’s tale would fit snugly into the narrative template of a Kenyan marathoner.

  If not for a batch of curious scientists who were familiar with Mäntyranta’s exploits and invited him to their lab twenty years after his retirement, his story might have remained a pure triumph of nurture. But illumined by the light of genetics, Mäntyranta’s life tale looks like something entirely different: 100 percent nature and 100 percent nurture.

  Obviously, Mäntyranta had rare talent. Just as clearly, he needed to train assiduously to alchemize that talent into Olympic gold. As psychologist Drew Bailey told me: “Without both genes and environments, there are no outcomes.” Instances in which a single gene has a dramatic effect, as in Mäntyranta’s case, are extremely rare, and finding athleticism genes is extraordinarily complex and difficult. But a present inability to pinpoint most sports genes doesn’t mean they don’t exist, and scientists will, slowly, find more of them.

  One of the concerns held by Yannis Pitsiladis, the scientist who traverses Africa and Jamaica to collect athlete DNA, is that discovering genes that influence athletic performance will detract from the hard work undertaken by athletes if those genes turn out to be more concentrated in one ethnic group or region than another. But we already know that certain ethnic groups have genes that equip them superiorly or inferiorly for particular athletic endeavors. To use Yale geneticist Kenneth Kidd’s example, we can agree that Pygmy populations are unlikely to be founts of NBA stars, given that Pygmies tend to have few gene variants that result in tall stature compared with other populations.

  Height is clearly an innate advantage in basketball. But does it detract from Michael Jordan’s achievements that he had the good fortune to be endowed with genes that contributed to his being taller than Pygmies, and than most other men on earth? If there exists a scientist or sports fan who would denigrate Jordan’s hard work and skill because of his obvious gift of height, I didn’t meet him in the reporting of this book. In fact, the opposite extreme—ignoring gifts as if they didn’t exist—is much more common in the sports sphere.

  Consider this title and subtitle of a Sports Illustrated story: “The Fire Inside: Bulls center Joakim Noah doesn’t have the incandescent talent of his NBA brethren. But he brings to the game an equally powerful gift.” The “gift” is Noah
’s desire to win. Never mind that he is the 6'11" son of a French Open tennis champion and has a wingspan of 7'1¼" and a 37½" vertical jump. If those aren’t incandescent athletic endowments, then what, pray tell, are? Noah’s lack of talent referenced in the headline—and by Noah himself in the story—would seem to describe the fact that he’s a graceless ball handler and mediocre jump shooter. Which, based on the sports science, probably has more to do with the specific work he has put in to develop dribbling and shooting skills than with his hereditary gifts. A more honest headline might read: “The Talent Outside: Joakim Noah has not acquired basketball-specific skills to the extent of his teammates, but he is at the upper extreme of humanity in terms of his physical gifts and therefore can be a good NBA player anyway.”

  Acknowledging the existence of talent and of genes that influence athletic potential in no way detracts from the work it takes for that talent to be transformed into achievement. The studies undertaken by K. Anders Ericsson—the so-called father of the 10,000-hours “rule”—and his colleagues typically don’t address the existence of genetically based talent because their work begins with subjects of high achievement in music or sports. When most of humanity has already been screened out of a study before it begins, the study often has little or nothing to say about the existence or nonexistence of innate talent.

  In reality, any case for sports expertise that leans entirely on either nature or nurture is a straw-man argument. If every athlete in the world were an identical sibling to every other athlete, then only environment and practice would determine who made it to the Olympics or the professional ranks. Conversely, if every athlete in the world trained in exactly the same way, only genes would separate their performances on the field. But neither of those scenarios is ever the case.* (The occasional example of same genes/same training tells the expected story. I was standing beside the finish line of the London Olympic 400-meter final when Belgian identical twins and training partners Kevin and Jonathan Borlée, despite running in lanes on the extreme opposite sides of the track, finished 0.02 of a second apart.) Athletes are essentially always distinguished by both their training environments and their genes.