The Argument
David Shenk reminds us that, “genes are constantly activated and deactivated by environmental stimuli, nutrition, hormones, nerve impulses, and other genes [which] explains how every brain cell and hair cell and heart cell in your body can contain all of your DNA but still perform very specialized functions" (22). How can you relate this idea to people who have “severe impairments and yet extraordinary abilities” as David Shenk explores the connection of autism and savant skills (89)? In other words, how can a gene be turned on to compensate for an ability we lack? Or, how can we actually induce a gene to be turned on—to improve at a particular sport, instrument, or activity? Consider this: bacterial cells have a selective advantage to survive and reproduce if they can save reserves and energy. Can you think of an example of a process that bacteria cells carry out that relates David Shenk’s idea about environment stimuli and gene regulation—and a biology theme?
Linda Xu (lindaxu22@hotmail.com)
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ReplyDeleteAs constantly expressed as a central theme throughout Shenk’s argument, the expression of genes is directly related to environmental stimuli: GxE (not G+E). In other words, it is not simply a sequence of DNA compounded with positive environmental factors that forms intelligence, but the interaction between the two factors that stimulate the process of developing intelligence. In the case of people diagnosed with savant syndrome, a very precise interaction between environmental stimuli and gene expression results in highly specialized skills and abilities. Darold Treffert, a leading psychiatrist at the University of Wisconsin, proposed that savant syndrome is a precise interaction between external stimuli and gene expression in that impairment of the brain’s left hemisphere allows for the right hemisphere to over-compensate for the impairment, leading to the vast capabilities of prodigious savants. Other savant researchers, who used magnetic pulses to deactivate the left frontotemporal lobe in otherwise normal individuals, further support this theory. Deactivating portions of the brain led to rather noticeable increases in “savant-like tendencies” (90) in the subjected individuals. However, this process does not automatically lead to innate intelligence, but provides the capability and framework for prodigious savants to develop highly advanced talents. The process thus fits Shenk’s proposition that intelligence is a process, developed by the complex interaction between genes and the environment, not a thing simply granted by genes or external stimuli.
ReplyDeleteAs evidenced by the savant studies, manipulation of external stimuli is a very plausible means of regulating gene expression. While there are currently no precise environmental triggers that would allow for the clear expression of genes to improve at a particular sport, instrument, or activity, continual practice of such activities can lead to enhanced ability by cognitive learning. In the case of bacteria cells, the ability of certain bacteria to develop resistant cells called endospores is directly related to environmental stimuli dictating gene expression. Upon encountering an unfavorable environment (lacking essential macromolecules necessary for survival), the bacterial cells codes for proteins that surround the copied chromosome with a protective wall. The resulting cell, the endospore, can survive for years with a halted metabolism, allowing for survival in unfavorable conditions (Campbell 560). In addition, the ability of bacteria to form endospores relates to the biological theme of regulation, as the endospore maintains homeostasis by forming a protective layer and halting its metabolism upon encountering an unsuitable environment.
Above Post: Nick Sotos (nsotos13@gmail.com)
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