Jamaica’s superb display at the recently concluded Games of the 29th Olympiad in Beijing, China has left many wondering how such a tiny nation of approximately 2.6 million people outrun nations such as the United States and Britain who previously dominated in the sprint events.
Jamaica’s sprinting tradition or evolution can be traced back almost 60 years, since 1952 when the quartet of Herb McKenley, George Rhoden, Arthur Wint and Les Laing set the stadium in Helsinki on fire by breaking the world record in the 4x400m relay. The country’s performance reached a zenith at the 29 th Olympiad and elicited responses of shock and disbelief. In a sport marred by illegal steroid use and recent gene doping, Jamaica’s record-breaking medal haul of six gold, three silver and two bronze has been met with suspicion and some amount of envy.
Why are Jamaicans dominating in sprint events at the international level? The University of Glasgow in Scotland and the University of the West Indies in the Caribbean are hoping to give definitive answers as to the cause of this phenomenon. Both universities have embarked on a collaborative study to examine the role of genetics, environmental and physical education/training in Jamaica’s athletics success.
Preliminary results from the first phase of the research, which was carried out over a two-year period, suggest a genetic predisposition in Jamaicans. We, the primary researchers at UWI’s Mona campus, have disclosed that DNA analyses carried out on 200 Jamaican Olympians with controls consisting of 200 ordinary Jamaicans showed that 80% of the Olympians have the strong 577RR variant of the alpha actinin 3 (ACTN 3) gene, which established research has proven is associated with fast-twitch muscle fibers that allow for high velocity or power sprinting. The actinin 3 gene is a performance-related gene and one must have the strong form 577RR or the weaker form 577RX to produce the protein alpha actinin 3 that is associated with power sprinting.
Most persons of West African ancestry have the 577RR or 577RX variant. Only about 2% of West African has the 577XX or null variant which does not produced the alpha actinin protein. In Jamaica, the null genotype is found in approximately 2% of the general population, while this cohort is 18% in the US, 20% in Europe, 25% in Asia.
It is very ironic that 70% of the ordinary Jamaicans tested has the 577RR variant. Where does that leave us? Am I saying that any Jamaican can be a Usain Bolt or Asafa Powell? Yes and no, and please do not be confused by my answer. Jamaicans are genetically predisposed based on their shared ancestry with West Africans; however, the gene/(s) has to be switched on or off by environmental factors and physical conditioning.
Let us use diabetes as an example. One might have a family history of diabetes but the disease is not manifested if one eats correctly and exercises. I have studied many families with diabetes and will speak of a classical family X. Mr. X’s mother had diabetes, his four sisters were a little obese and all had diabetes before age 35 years. Mr. X’s six daughters and one son had diabetes but Mr. X never developed diabetes because he walked 10 miles per day, was a vegetarian and remained lean all his life.
The Gene Environmental Effect
The DNA samples were analyzed for another performance-related gene, the angiotensin converting enzyme or ACE gene. This is involved in the whole regulation of blood volume and blood flow. The percentage of ACE in our Olympians is higher than the figure for the general population. The DD and DI variants of the ACE gene were found in the Jamaican Olympians. These variants are associated with cardiac hypertrophy. This might allow one to hypothesize that Jamaican Olympians might have larger hearts as compared to other Olympians. Large heart can consume more oxygen during sprinting. The aerobic or oxygen pathway is utilized in endurance running.
So, based on their genetic make-up, Jamaican Olympians are able to utilize the anaerobic and aerobic pathways in the sprinting mechanism. Sprinters usually use the shorter pathway (anaerobic) where glucose is broken down to give pyruvic acid which gives short bursts of energy for sprinting.
In addition to carrying out DNA analyses on Jamaicans who participated in the 1948 Olympics right through to those who participated in the 29th Olympiad, tests were also conducted on 400 national athletes and 350 persons from the Cockpit Country/Trelawny region. The latter cohort was included because many Olympians have emerged from that area or have links there. Interestingly, the profile of the persons from the Cockpit Country is similar to that of the Olympians.
“The phenomenon seen in the Cockpit Country region
of Jamaica could be similar to the one found in
the Rift Valley region of Kenya, which has proven
to be a fertile area for the development of
world-beating athletes in long distance e vents.”
Most of the population of West African ancestry has the gene variant for sprinting. Having the 577RR or 577RX variant of the actinin 3 gene does not explain why Jamaicans dominate in international sprint events. There must be something driving this gene and or other genes to perform to the full potential. When something drives a gene or switches it on or off, it is termed gene environmental effect. We postulate that there are special minerals (something like the bauxite in the Cockpit region that affects botany) such as minerals from the Cockpit Country that the plants uptake and Jamaicans eat in yam and other tubers. Remember, many of our Olympians such as Usain Bolt, Veronica Campbell, Donovan Bailey and Deon Hemmings come from that region. Even more of our Olympian parents are from the Cockpit Country.
Muscular properties are subjected to inherited influences. Muscle fibers numbers are determined by the second trimester of pregnancy. So even before birth our Olympians are influenced by their environment.
The phenomenon seen in the Cockpit Country region of Jamaica could be similar to the one found in the Rift Valley region of Kenya, which has proven to be a fertile area for the development of world-beating athletes in long distance events.
In addition to all the foregoing reasons, physical education has come a far way in Jamaica and we are fortunate to have a program in our schools and events like Boys’ and Girls’ Champs. We are also fortunate to have the GC Foster College, which puts out coaches so that our schools have qualified persons to help with the training of the athletes.
The Jamaican program definitely has had an impact. We have something that is certainly working and even the IAAF president, Lamine Diack, has praised it.
Contributed by Dr. Rachael Irving & Vilma Charlton
Irving is a research fellow at the University of the West Indies, Mona, Jamaica and the lead researcher in Jamaica for the project.
Charlton, former Olympian, is a lecturer in the Institute of Education, University of the West Indies, Mona.