Evidence
In footnote 27, Maze-dull rats were compared to Maze-bright
rats. The Maze-dull rats “consistently [test] poorly in [the] same mazes,
making an average of 40 percent more mistakes” (193). Shenk uses the Maze-dull
and Maze-bright rats to illustrate the point that environment really determined
the performance of the rat in a maze. However, when looking at the graph on
page 29, it is easy to see that there is a large disparity between Maze-dull
and Maze-bright performances when the rats are placed in normal environments,
rather than the two extremes of restricted and enriched environments. Doesn’t
this prove that although environment can alter the outcome in extreme
conditions, in average conditions, genes tend to play a much larger role than
the environment? Does this mean that genes really are the biggest players in
genetics? In footnote 41, Sherman and Key state that “children develop only as
the environment demands development.” This conclusion aligns with the
experiment with the rats. Therefore, are most of our traits and talents
inherited? If humans are placed in extreme conditions, will they develop in
response to the change in demands of the environment? What is the real effect
of genes on organism development? What affects development more, genes or
nature? Look to Chapter 14 and 15 to explain inheritance and phenotypes in more
detail, and relate to the biological themes of continuity and change,
interdependence in nature, and/or regulation.
Annie Lee (xxannie.leexx@yahoo.com)
Although genes do play a vital role, especially in the GxE development model, genes are still not the biggest players in genetics. Genes are important in phenotype and variation, but development is based more on the environment as much as genes. The departure of simple Mendelian genetics arises when the phenotype of a character depends on the environment as well as the genotype (Campbell 274). Although Mendelian genetics is important for characteristics, other factors like polygenic characters and multifactoral characters which both rely on the environment just as much as genes. For humans, genes are not associated with a rigidly defined phenotype, but rather a range of phenotypic possibilities called the norm of reaction for a genotype based on the environment. The GxE model supports the idea of having both genes and the environment playing a basically equal and strong role in development. In the case with the maze dull and maze rich rats, their “genetic differences” basically disappeared because they were all raised in an impoverished environment (29). On the other hand, genes played a significant role as the Maze-dull rats “consistently [test] poorly in [the] same mazes, making an average of 40 percent more mistakes” (193). In the end, the debate between whether nature or nurture cannot be settled definitely and genes are not the single biggest players in genetics.
ReplyDeleteThe statement that “children develop only as the environment demands development” (Footnote 41) would suggest that most of our traits are talents are not exactly inherited but interactions with the environment had help develop traits and talents. Concerning traits, the environment can influence the phenotype through multifactoral and polygenic traits. Both traits and talent still relate to the GxE model of development and how both surface from the interactions between both genes and the environment. People like Tiger Woods, Leonardo da Vinci, and Richard Feynman are all influenced by the GxE development to obtain their traits and talent. No matter what genes someone has, the environment must demand further development in order to obtain better talent and traits. Traits and talents are not inherited, but the environment must interact with the genes in a way that dynamic development will be at its fullest potential. Genes and the environment both relate to everything from athleticism to personality to a person's predisposition to obesity (http://www.livescience.com/4168-nature-nurture-mysteries-individuality-unraveled.html). This relates to the theme of interdependence in nature and how our phenotypes are the synergistic product of genes and the environment. When humans are placed in extreme environments they must develop to interact with the environment and survive, which relates to continuity and change in genetics as the organisms with the fit traits will be naturally selected. The role genes have in organism development is to trigger the production of proteins, which can guide the functions of cells which will then interact with the environment to form traits. On the other hand, the environment can switch genes on and off in regulation. Both genes and the environment play a crucial role in development and one is not necessarily more important than the other. Both are needed to work for dynamic development to be at its fullest potential. That way, traits and genes are formed from people who have the best of the combination between genes and environment interaction.
(Kirk Chiu- krkpchiu@gmail.com)