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Thursday, Aug. 12, 2004
Sensitive science in the race for glory in athletic pursuits
By ROWAN HOOPER
With the 28th Olympic Games about to start, who would put a bet on a white athlete winning the 100 meters? Certainly not the American writer Jon Entine. "The complete domination of the 100 meters by people of West African origin means no white man will ever again win the event. It simply won't happen," said Entine, when promoting his book "Taboo: Why Black Athletes Are Better and Why We're Afraid to Talk About It" (PublicAffairs; 2001).
It is not easy to discuss the issue of black domination of certain athletics events. When Roger Bannister, an English neurologist and the first man to break the 4-minute mile, said in 1995 that "black sprinters and black athletes all seem to have certain natural anatomical advantages," he was condemned as a racist.
But the question remains: Has natural selection in parts of Africa predisposed black people to be better at modern athletics?
In 2000, a Danish sports scientist, Bengt Saltin, published the results of a study of athletes in Kenya. Saltin and colleagues had spent 18 months in the town of Eldoret, in the Rift Valley province where the Kalenjin tribe live. Remarkably, Kalenjin athletes account for 40 percent of the world's top distance runners.
Saltin pitted Kalenjin schoolboys against one of Denmark's top professional athletes, and the schoolboys won.
"Kenyans are more efficient because it takes less energy to swing their limbs," said Saltin's colleague Henrik Larsen. Or to put it another way, Kenyans bounce, but Danes thud.
And what of the sprinters? When you look at the statistics, you have to wonder about the fuss caused by Bannister's comments: No white man has run the 100 meters in under 10 seconds, and the 200 fastest times are all held by black men.
Of those sprinters, most are from West Africa or of West African ancestry. For example, Carl Lewis, who in Tokyo ran the 100 meters in 9.86 seconds and won nine Olympic gold medals, has West African roots.
Bannister caused controversy because he was treading on very sensitive ground. There is a deep worry that if you admit that black people can run faster, and faster for longer, than white people, then it is but a short step to admitting other differences.
But what is the explanation for the phenomenal success of black athletes? The Kalenjin live above 2,000 meters: Does the high altitude boost their oxygen-uptake efficiency? What about black sprinters? Do they, as some researchers have found, have more of the fast-twitch muscle fibers that can generate energy at high rates?
In other words, it's the old genetics/environment question. How much is nature and how much is nurture?
"There are definitely some genes that are special here. The genetic inheritance is there." Mike Boit, a Kenyan gold medalist at the 1978 Commonwealth Games, and present head of physical education at Nairobi's Kenyatta University, said on a British television program in 2000.
What would a professional scientist say? "I'd say it's 55:45 genes to environment," Michael Rennie, Professor of Clinical Physiology at the University of Nottingham Medical School in central England, said in an e-mail interview. He pointed out that even identical twins can turn out very different, giving as evidence the case of Otto and Ewald, German identical twins, one of whom became an endurance runner, the other a power athlete. "Looking at them shows the power of endurance versus strength training," said Rennie, who emphasized that, for most traits, genes do not account for even 55 percent of the variation between individuals.
Of course, if you are a genetic freak then this will make a big difference, Rennie noted. "For example, if you have a double mutation in the myostatin gene, you are going to have big muscles." Rennie was referring to a paper in the June 24 issue of the New England Journal of Medicine. An international research team investigated a German child born with unusually well-developed muscles, and found that the muscles were the result of a mutation in the myostatin gene.
Myostatin is a protein that normally keeps muscle development in check; the boy's mutation shows that without the protein, muscles quickly bulk up. An athlete with this mutation would clearly have a big advantage. "However, genes with this sort of effect are rare," said Rennie.
"Candidate genes for high levels of athletic performance have so far usually proved to be minor in their effects." One gene that has caused excitement is that for angiotensin-converting enzyme (ACE). A version of the gene enhances oxygen uptake and is apparently widespread in endurance athletes. To test this, sports physiologist Yannis Pitsiladis of the University of Glasgow went to East Africa. His team took DNA samples from Kenyan and Ethiopian athletes, and found that the oxygen-uptake version of ACE was more common in them than in men from the general East African population.
Saltin's study of Kenyan runners found they had narrower calves than Danish athletes. "This reduces inertia in the lever about the knee, and gives about an 8 percent mechanical advantage," said Rennie.
As always, more research is needed, but on balance it seems that natural selection has favored traits in certain West and East Africans that help them excel in certain modern athletics events. And though the power of psychology -- the will to win -- should never be discounted, it would be a waste of money to bet against a black athlete winning the 100 meters.
A book of Natural Selections columns translated into Japanese, "Nou to sekkusu no seibutsugaku," is published by Shinchosha. Rowan Hooper is a biologist at Trinity College, Dublin. He welcomes readers' questions and comments at email@example.com