Presented in Chapter 4 of The Argument is the idea of clones. With Ted Williams, his son John preserved his body in hopes of cloning him later to one day have another amazing baseball player. Consider the development unit and discuss the weaknesses and strengths of the idea of cloning cells. Explain the weaknesses and strengths of cloning due to factors such as the book's argument of GxE versus G+E and how there is the impossibility that the William clone will receive the same experiences to become the Ted William. But also include totipotent, pluripotent, and multipotent cells and which one is needed to clone and which ones the frozen body of William would have. (Here is a quick reminder of the types of stem cells: http://www.stem.com/stem-cell-facts/potency-of-stem-cells/) Where would these cells be found in the body?
(Diana Liao - dianaliao3@gmail.com)
One of the primary arguments of David Shenk is that it is the combination of all our life events and experiences that contribute to our gene expression and it is essentially this gene expression which leads to almost every person in the world being unique. One great example of this although it is not exactly cloning is shown on page 83 with the two identical twins. Shenk states that twins are probably the closest to cloning since they share some of the same genetic material; not only that, but they also share an early gene-environment by sharing the same womb. In this sense they receive the same nutrients and all the possible experiences that the mother has during her pregnancy is equally imprinted for both the twins. And yet, it is because of different gene-environment reactions that occurred after birth that the two boys ended up so different. The long distance runner, Otto, became lean and the strength competitor, Ewald, became extremely muscular.
ReplyDeleteIndividual activities in our body create different effects, and create different needs for gene expression. Gene expression is regulated by our body through a variety of different processes. One of the ways to reduce gene expression is through gene silencing. This process can be achieved through histone acetylation or by DNA methylation both of which reduces gene expression. There are also methods which can increase gene expression such as specificity factors which can make RNA polymerase more likely to bind as well as enhancers which are sites on the DNA helix that can bring in specific promoters to the initiation complex. The activity of long-distance running is more likely to induce a softer volume in gene expression for anaerobic muscles. Long-distance running develops oxidative aerobic muscles that can sustain long-distance running and long time production of ATP through metabolism. This is one reason why we can see the muscle tone difference between the runner and the strength trainer, even when their genes “should” according to G+E theory create same body builds as opposed to the GxE theory which is better supported.
In terms of potency and stem cells: cloning of the Kid might be able to create similar appearances and qualities to some extent. Especially because the of embryonic stem cell research that could develop in the future. Totipotent cells are able to differentiate into all types of cells in the body, pluripotent can differentiate into the three different germ layers, multipotent allows cells to change into different type of body cells but not into different germ layers. Embryonic stem cells are only found in the blastocyst in the middle of the blastula. The cells in Ted William’s frozen body would be regular somatic cells and therefore would not be able to differentiate into a new organism.
Sources cited: http://www.plosbiology.org/article/info%3Adoi%2F10.1371%2Fjournal.pbio.0020322
http://en.wikipedia.org/wiki/Regulation_of_gene_expression
http://www.stemcellschool.org/ig-stem-cell.html
kevin.liuxu@gmail.com
Kevin Xu