Susie Shin (susieshin94@gmail.com)
Friday, March 23, 2012
Argument- Gene Expression
Shenk states that "precisely, which genes do get switched on, and when and how often, and in what order, will make all the difference in the function of each cell- and the traits of the organisms” (32). From this quote, try to describe specific processes in which genes may be switched on or off in animals. How does timing of these genes being switched on and off affect gene expression and the traits that come with. Go back to the Hart and Risley experiment and look again at how "genetic differences do exist" (46). Include the triggers to answer how we can ultimately change our certain traits through environmental influences?
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Part of what makes humans, and life in general, so adaptable is the ability to regulate gene expression. Now, this can occur in a multitude of ways, and differs among eukaryotes and prokaryotes, but the basic concept is the same – organisms can respond to changes in the environment and current needs by changing how a certain gene is expressed.
ReplyDeleteThe list of techniques for gene expression goes on and on: operons in prokaryotes regulating metabolism, differential splicing in mRNA changing the expressed protein from the same gene, DNA methylation and histone acetylation in eukaryotic chromatin regulating transcription all serve this purpose (Campbell 352-358).
Now, the Hart-Risley experiment (Shenk 47-48) demonstrated that children that had certain triggers in early development, such as being spoken to often, early reading, encouraged, having high expectations, embracing failure, and having a growth mindset gave them significant advantages in school.
Each child did have their own genetic differences that certainly affected their performance, but these environmental triggers, occurring before the age of three, had a special impact. Shenk’s model of GxE demonstrates the profound impact that environmental factors and genetic factors have on a person’s traits. These children most likely had a more sensitive period at this young age that allowed the new environmental factors to affect their gene expression. The poorly understood epigenome likely had a significant role in these changes.
These epigenetic influences further link genetics and environment, and are the major factor in which genes are “turned on” or “turned off”.
David Whisler (dwhis428@gmail.com)