Starting on page 81 and the chapter "Can White Men Jump?", Shenk brings up the common belief or stereotype that race can determine athletic ability. One example is how the small island of Jamaica captured six gold medals in track and field and eleven medals overall in the 2008 Olympics. He wonders how such a small place can win so many medals in a specific event. Within hours of the wins geneticists studied what force it was that drove Jamaicans to be such fast runners. They discovered that 98 percent of Jamaicans possess the gene variant called alpha-actinin-3.
What does the gene alpha-actinin-3 actually do? What actually causes certain populations to be better at a sport than other populations? Do you think certain abilities have evolved more in African countries as opposed to North American or European countries due to natural selection? Give an example. Are racial and ethnic groups generally genetically different? Overall, do you think genetics or something else allows for some populations to produce better athletes than other populations?
The gene variant ACTN3 is present in fast-twitch muscle fibers, which are responsible for generating force at a high velocity (http://www.ncbi.nlm.nih.gov/pmc/articles/PMC 1180686/?tool=pubmed). This leads scientists to believe that this protein is responsible for outstanding runners. However, as determined in a scientific study, individuals with the variant R577X in which the ACTN3 is completely absent due to a premature stop codon were strongly associated with elite athletic status (http://www.ncbi.nlm.nih.gov/pubmed/17211191). Thus, ACTN3 does not seem to be the source of elite athletes. To contribute further to this idea, although 98% of Jamaicans have this gene variant, 80% of Americans and 82% of Europeans also possess it. This leads to the conclusion that ACTN3 is not the sole factor in producing elite runners; if it was, America and Europe would have a much high percentage of elite runners than it currently does.
ReplyDeleteInstead of strictly genetics, I think it is more the mentality and competitive atmosphere that spurs great athletes. Sure, 98% of Jamaicans possess the ACTN3 gene variant, but all Jamaicans are surrounded by an intense competition that is unique to their region. In Jamaica, running is a central part of their culture. The children run to school, run home, run to the river, and back. Therefore, they focus heavily on running, with the growth mindset that “we’re small and we’re poor, but we believe in ourselves” (Shenk 110). This mental plasticity and ability to grow and develop skills creates way for enormous athletic potential.
Despite the importance of a stimulating environment, I think it is also probable that certain traits have evolved in African countries instead of in Europe and North America due to natural selection. Natural selection is defined as the process in which individuals with certain characteristics are more successful in survival and thus pass on their traits to more offspring than individuals with other traits (Campbell 456). Millions of years ago, humans roamed the savannah in Africa, running from predators and hunting prey to consume. Natural selection would have favored those with the fastest running speed and longest running endurance, because they can escape from predators the most effectively (thus avoiding death) and capture more prey than humans with slower running speed and lower endurance. Therefore, the fastest runners would have escaped death and captured food most frequently, and would be able to pass on their genes and know-how to the next generation. As humans migrated away from Africa to different countries, the urgent need to be exceptional runners no longer persisted.
Generally speaking, genetic differences between different ethnic groups are very slight, most of the variation is between individuals (Shenk 106). Thus, like stated earlier, it is not strictly genetics that produces certain kinds of people. Instead, if the environment demands great runners, than there will be increased likelihood that that is what they will become.
Diane Kuai (dianekuai@gmail.com)
I agree with Diane that great athletes come from a positive mentality and a competitive environment which creates a drive within them to do better. The ACTN3 gene may help Jamaicans to be slightly better at running, but with a growth mindset, people can strive to be whatever they want to be. Diane also points out a good point in the topic of natural selection which is that millions of years ago in Africa, traits to help humans run fast were favored because they needed to escape from predators and capture food. These traits were passed down, but as humans migrated from Africa they didn’t have to use those genes as much so the genes slowly faded away. I also agree with her statement that the genetic differences in ethnic groups are slight and that the individual is what causes most of the variation.
ReplyDeleteAlpha-actinin-3 has not had its full function been discovered, but it has been recently shown to influence muscle strength in non-athlete women. All work so far has shown that ACTN3 has an effect in human muscle health and fitness (http://www.chw.edu.au/research/groups/neurogenetics/02_actinins.htm).
I think that certain populations are better at sports than other populations because of the environment they were brought up in and what their lifestyle is. If their environment encourages sports and they have a drive to get better, then the population will do well in sports, but if they are lazy and are encouraged to get a job or do other activities, then the population will not do as well. It is more about the individual and how he or she is motivated into being an athlete that will determine if the population will have a big number of athletes.
I think that certain genes have been turned off in North American or European countries due to evolution/natural selection and African countries still have the genes turned on because it helps them to survive and get places. Kenyan tribes are especially known for their running because they are so good, but it comes from their environment. They must run many miles as part of their daily routine. They run to school and back, to the river and back, run home, and then to the school—basically everything is running (103-104). Here in America we have buses and cars to take us where we need to go so we don’t need the ACTN3 gene that the Kenyans have because we don’t need to run everywhere and it has been turned off over the course of time because of natural selection/evolution.
In Campbell, we learned that the human genome is very much alike, but there are non-coding regions which create the small differences that make each person different. Also, there is RNA splicing which can alter gene expression and causes changes in the body as well. So yes, racial and ethnic groups are genetically different but all people are slightly genetically different. However, in the long run all humans have a similar genome so that we are similar, but with different traits and I think that makes humans no matter their race or ethnicity all alike. (Regan Frieling, regan1995@yahoo.com)
Like Diane said, ACTN3 is related to muscle contraction, and some might think that this would directly relate to running. However, studies have shown that this does not have a tremendous effect on running. Also, Shenk talked about how many other people from different countries also have the same gene. Even though there is only about a 15% increase in the frequency of the gene from Jamaicans and Americans, Jamaicans have a much higher representation in running than just 15% more than Americans or other countries. Thus, ACTN3 is not the main reason why Jamaican runners are superior.
ReplyDeleteHumans, while their genes are different, are all born with pretty much the same capabilities, barring disease and illness. The reason why Jamaica produces so many excellent athletes is because their culture celebrates athletic ability in running and places a much higher value on it than countries like the U.S., which focus more on sports like football or basketball. Running is basically their way of life, as everyone young and old has to do it, and there are major rewards for becoming a good runner. No other country places that much emphasis on that sport, which is why Jamaicans are dominating in their field.
Most likely the Jamaicans do have different genes, passed down from ancestors who might have been cattle-raiders or herders, where the ability to run determined life or death. However, you could also argue that European genes would make Europeans stronger because in the medical period, warfare was frequent and common. However, not every European is a strongman, while a lot of Jamaicans are good runners. This again demonstrates the idea that environment has a much greater role in gene expression. In the end, it is the culture that shapes people into perusing athletics with enough passion and dedication to become great
David Wang dwang95@gmail.com