David Shenk talks about the racial, yet humorous, adage that white men can’t jump. By extension, he incorporates general athletics such as the 2008 Olympics and Jamaica and Kenya’s impressive competitors. His main point is that a “culture of extreme excellence…begets success” (105). He disproves the gene-centered theory of natural ability by ethnicity or even region.
How does this apply to the biological system of “positive feedback loop[s]” (108)? Use specific examples from class or Campbell and relate it to the culture of track and field in Jamaica or running in Kenya. Would small, seemingly isolated, regions of athletic success support a Darwinian example of natural selection? Take into account that on page 101, studies show that Jamaicans had the highest percentage of ACTN3 gene that allows for “forceful, speedy muscle contractions.” Is there at least some truth to genetic advantages?
According to Shenk, "the single best way to inspire better performance is to be surrounded by the fiercest possible competitors and a culture of extreme excellence" (105). This explains the positive feedback loops in that those that are successful, are able to thereby achieve more, bringing their society as a whole to better and better accomplishment.
ReplyDeleteThe application to positive feedback loops is that success results in more success. This is modeled by the Flynn effect mentioned by Shenk earlier in which our world has become exceedingly more intelligent over time and intelligence seems only to result in the next generation being even more intelligent. As to why this is true, Shenk seems to stipulate that it could either be a result of actual genetic change occurring over a short period of time such that gene expression is passed from mother to child, or that the environment is changing as a whole. Shenk's most clear point, however, is that evolution is not occurring at this rate.
To explain the idea of evolution a little further, evolution is a very slow process that happens over hundreds of thousands of years as mutations allow for survival. There are really two main reasons that evolution cannot be behind the Jamaican's running habits. First off, there has been a lack of sufficient allopatric speciation in which “gene flow is interrupted when a population is divided into geographically isolated subpopulations” (Campbell 492). Shenk points this out in saying that “Jamaica… may represent a ‘crossroads’ with the Caribbean” (Shenk 108). This means that not only are Jamaicans more closely related to whites genetically than was once believed, they also have not been very isolated from external genetic influence.
A second reason to explain why genetic differentiation likely has not occurred is the lack of an environmental stressor. The idea of survival of the fittest requires that those that are not fit do not survive in order to reproduce. The reality of the human population today is that many people who are rather unfit and need constant care, are able to reproduce, so despite genetic disadvantages, many people continue to survive, and there is no reason that the Jamaican population should be exempt.
In regard to the ACTN3 percentage, it does appear that genetics may play some role in athletic performance. This is illustrated by
“Pimenta, E., Coelho, D., Cruz, I., Morandi, R., Veneroso, C., Azambuja Pussieldi, G., & ... Paz Fernández, J. (2012). The ACTN3 genotype in soccer players in response to acute eccentric training. European Journal Of Applied Physiology, 112(4), 1495-1503. doi:10.1007/s00421-011-2109-7”
In which the conclusion was made that “athletes homozygous to ACTN3XX gene are more susceptible to eccentric damage and present a higher catabolic state, demonstrated by metabolic, hormonal and immune responses post an eccentric training, in comparison to ACTN3RR and ACTN3RX groups” (Pimenta). In this light genetics may play some role in recovery and development of muscle, much like genetics can guide height. As Shenk points out however, following the GXE ideal, many who are homozygous for this gene will not live in an environment to express it, and on the other hand, many who do not have this gene will find a way to survive in an environment where it would have been helpful.
Ultimately, it appears now that though white men might not often jump as high as other cultures, this is a result of missed potential, and not genetic differentiation.
Jacob Yomtoob (jakeyomtoob@gmail.com)