On page 108 Shenk brings
up an alternate view of cattle-raining Kenyans shared by developmental
biologists; that is, instead of the quickness genes being passed on and driving
natural selection towards better runners, “crucial external ingredients” such as as “propitous
attitude and habits”, “access to the best trainers”, and “leisure time to
pursue training” are passed along.
Relate to the biological themes of evolution
and change. Using examples from modern society and/or science are the “external
ingredients” or “quickness genes” more influential? How could this apply to the
biological system of a positive feedback loop?
It is generally very hard in real life to distinguish between genes and environment influences on a person's abilities. However, there are many instances throughout history of people 'rising to the occasion' based on their environmental situation. In the centuries of battles and wars, there were many very skilled and celebrated warriors and soldiers, remembered even today, such as Achilles or the Maccabeus brothers. In the modern world of bombs, guns and tanks we are less likely to find that talent in society. That definitely makes it seem more plausible that the 'external ingredients' hold more weight with a specific culture/society's cultivation of a specific skill rather than breeding and genes in the society. If it was the evolution of genes driving our cultural specialties, it would not have been possible to shift to quickly from a medieval to modern culture. Evolution and natural selection take centuries to show results of a visible magnitude.
ReplyDeleteTo this point, it may be more of a societal than biological positive feedback loop. When we notice that something works, we go back for more, and the more it works, the more people go back for more. This process also points out the difference in time line between environment development and gene development. As humans, we can improve based on judging which ability or process would be better to cultivate. However, evolution can do no such thing. It is not a thinking entity rather it mindlessly favors survivors, by no means necessarily the 'cream of the crop.' Again, this points out that the salient factor in societies cultivating certain skills points to environmental, not genetical, factors.
Emily Reinherz...ereinherz@aol.com
There is always a great debate over the well know cliché “nature vs. nurture”. While there is evidence supporting both sides, David Shenk tells is that a human is the product of both: gene-environment interaction (GxE). His argument about epigenetics holds very true, yet it raises the further question of which factor is more influential. From my reading of this book, I believe that “external ingredients” and cultural/parental influence really is the dominant factor in human development.
ReplyDeleteTwo examples that show the strength of pressure and conditioning from outside sources are Wolfgang Mozart and the Kenyan runners. Mozart was conditioned from birth to play instruments and had a wide variety of factors such as his sister, his father and home that contributed to the outcome of his abilities. Mozart had a predisposition to musical talent as his older sister was a child prodigy as was his father who ended up mentoring him. Without the crucial factors of those two major influences, Mozart would probably have been a gifted musician, yet he never would have reached the glory that he had accomplished.
The Kenyan tribe of runners also illustrates this point well. Their culture is based in running. It has been in their culture for generations. They need to be good at running to survive. This is why I make the case that culture is a stronger influence on people. A child could be brought into this Kenyan tribe with a genetic defect that exposes him to obesity, alcoholism, heart failure, or any number of other factors that may keep him from being a skilled runner. Yet, growing up in a culture that demands running would force this child to adapt and become a good runner. David Shenk mentions on page 103 that a child in this tribe would “run many miles a day as part of his routine. (they would) run from the farm to school and back… would run to the river, take a shower, run home, change, run to school…” The Olympic runner Keino was quoted by Shenk in saying that in this tribe “everything is running”. This child would be conditioned from early childhood to run and these early influences may even overcome his/her genetic predisposition to diseases. As in the case with athletes, “training” takes its toll on the body, but also leaves it transformed in a completely new way. Tom D. Brutsaert and Esteban J. Parra published an article in the scientific magazine Respiratory Physiology & Neurobiology called “What makes a champion? Explaining variation in human athletic performance” which stated that “Elite athletes may be born with a favorable genetic constitution, but to realize athletic potential requires years of focused training. Training is itself a kind of self-imposed environmental exposure, and when gifted athletes train this could be considered an example of gene–environment correlation. The effects of training on performance variation can be dramatic”.
Therefore it is my argument that external ingredients play a bigger role in shaping a human. While good genes may give a person an initial advantage or an urge to develop a skill, ultimately, genetics can be overcome with culture, parental influence, or simply perseverance and drive to be different
Sorry, Blogger wouldn't let me fit it all into one comment. This is the rest.
ReplyDeleteEmily Reinherz stated in the previous response that “to this point, it may be more of a societal than biological positive feedback loop”. I disagree with this and I believe that there are multiple ways that a positive feedback loop could relate to this concept. The Campbell Textbook explains the concept of positive gene regulation in E. coli on page 355. It describes the interaction of an allosteric regulatory protein with an activator. An activator is “a protein that binds to DNA and stimulates the transcription on a gene”. Is it then possible that in humans, an environmental factor may stimulate the production of a certain “activator” that may stimulate more transcription of a gene. Is this a possible way that humans can change their own genetics? Much about epigentics still remains unknown but a kind of positive feedback line reproducing effective genetics may be present in our bodies.
Another application of a positive feedback loop to this concept is presented through the passing of genes from a parent to a child. As David Shenk states on page 103, if a man from this Kenyan tribe is skilled at running, he would own more cattle. If he owned more cattle, then he was richer and attracted more wives. Therefore a faster man would produce a greater amount of children with his same genetics. Therefore, his proficiency in running would create a positive feedback loop in this tribe, where these genes would be selected to be passed down and therefore thrive, spurred on by their own efficiency and abundance.
(Liz Gorelick lizgorelick@yahoo.com)
Genes are the not the only factor that can affect the outcome of an individual. The concept of nature versus nurture comes into play during this discussion. The way someone is brought up and the values and culture that surrounds them also affects who they will be. Kenyans are known to be better runners than most people which is why some people believe they have the “quickness gene.” However, “external ingredients, such as knowledge and means to attain maximal nutrition, inspiring stories, the most propitious attitude and habits, access to the best trainers, [and] the most leisure time to pursue training” (Shenk 108) can also affect the reason why many Kenyan people can run fast. Many people fail to realize that nongenetic factors can also affect someone in a significant way. Another group of people known for its exceptional athletes are Jamaicans. Many people believe that the reason for this is there African ancestry, but in reality “Jamaicans are…less genetically African and more European and native American” (Shenk 108). The reason for their success in athletics might be because of the stress schools and institutions put on competition and the popularity of track events.
ReplyDeleteExternal factors are much more influential on an individual than genes. The genes a person has is the starting point of a certain factor, but how that factor is expressed is determined by the environment that surrounds the individual. Typically in schools, students with an Asian or Jewish background tend to score higher than other ethnicities. “The high academic and occupational attainment of Asians and Jews is not due to higher IQs, but to family values that emphasize accomplishment and intellectual attainment, and to cultures that emphasize hard work and persistence” (http://www.ur.umich.edu/0809/Feb02_09/05.php). Different ethnicities contain different values that a child growing up will continue to express throughout their life. Also, the reason for the United States being behind the other countries in academics is because of the culture. Other countries stress education at the utmost importance, while Americans don’t have education in their culture as the number one priority. The reason for the education gap between American children and Asian children is not because of their genes but because the culture and environment where they grow up.
Through evolution, these changes in cultures have occurred making different types of groups excel in different aspects. This process could be viewed as a “positive feedback [loop], in which an end product speeds up its production” (Campbell 11). A culture that stresses the importance of education gets passed on through generations making most people in that culture well-educated and scholarly. This positive feedback loops has made our society advance and given humans the success they have today.
Anisha Ghosh (anishaghosh16@gmail.com)
With the emergence of a new model for development, GxE, came the idea of dynamic interaction between genes and the environment. We have learned from the model GxE that genes, proteins, and environmental signals constantly interact with each other. Thus, it is impossible to distinguish between “quickness genes” or G, and “crucial external ingredients” or E. Shenk calls genes and their environment “as inseparable and inextricable as letters in a word or parts in a car” (33). That said, some examples do show more influence from G or E. One example is the cloned cats that Shenk mentions in his book. Scientists cloned Rainbow the cat to make cc, short for carbon copy, but cc has a different coat and personality from Rainbow even though they are genetic copies (http://www.cbsnews.com/2100-205_162-537380.html). The cloned cat is an example of the impact of the environment.
ReplyDeleteIn Emily’s example, she mentions Achilles and the Maccabeus brothers as talented soldiers that show the effect of “crucial external ingredients” having a greater impact. However, it may have been that they were born with talent that made them good soldiers and that talent was amplified by that society’s focus on fighting. It is impossible to tell because genes and the environment are so intertwined. Campbell describes eukaryotic gene expression as cells continually turning genes on and off in response to signals received from the environment inside and outside the cells (356). In addition, Campbell also describes how the average human cell only expresses approximately 20% of its genes as one time” (356). This shows that even those with genes that make them better at one skill may not have those genes expressed. One implication that this has for evolution is that the organisms that chosen by natural selection do not necessarily have the best genetic combinations out of the population, but they were lucky because the genes that were expressed allowed them to survive and reproduce. Other organisms could have had better genetic combinations but didn’t receive the environmental signals that would turn on those genes.
The biological system of a positive feedback loop is defined by Campbell as a process in which the end product speeds up its production (11). Evolution relates to a positive feedback loop in that the ultimate goal of evolution is to produce an organism that can better survive its surroundings which in turn could make more organisms that could adapt to and better survive their surroundings. The improved organism that comes out of that combination of G and E produces improved offspring after mating with another improved organism. In this way evolution, or the survival of the fittest, ensures that the best organisms continue forward.
Jessica Hua (jhua33@yahoo.com)