When an ovum is fertilized and
the zygote divides into two separate embryos, monozygotic twins occur. Shenk
rejects that twins share an average “60 percent [intellectual] preset from their
genes while the remaining 40 percent [get] shaped by the environment” (78-9).
To suggest a more accurate idea for why identical twins develop to be as they
are, Shenk provides an explanation saying that an “early shared GxE” (80), and
a “shared cultural [circumstance]” (81) is what leads to this phenomena. If an
experimental zygote were to (1) be split and subject to the same environments
in identical ‘simulated’ wombs, then later, (2) each is reared by two separate
parties of similar cultural tendencies, could—if disregarding the small
differences in the culture and traditions of each family-- it be possible to
raise virtually the same organism in two different places? In other words, can
a zygote be duplicated and then separated from the other and still produce two
organisms that can be identified as ‘identical twins’? Where would the faults the strengths of such a
method occur? How can this form of cloning improve the human understanding of
continuity (the idea that a species stays relatively the same)? Relate your
answer to two biological themes and Chapter 15, 16, 17, OR 18 of Campbell (don‘t
forget the required outside source). Also, explain your bioethical stance on
this method—what bioethical principles does this break/amend?
-Jesse Pukshansky (jesse.pukshansky@gmail.com)
Based on the parameters of the ideal experiment, it would be possible to raise identical humans because the same genes are being affected by the same environment, but they would not be clones in the public sense. These identical twins would have similar traits, features, and characteristics, but they would possibly not have the same personality. A special case was in the Jim twins. Shenk describes that for the long lost identical twins, “it was like interacting with a living mirror. Not only did they look and talk the same, it turns out their lives uncannily resembled each other’s. They had each married and divorced a woman named Linda” (75). In this bizarre case, the two twins led almost identical lives physically; however, Shenk also notes many dissimilarities: “They wore their hair differently. One was much more verbally articulate than the other...”(83). Their physical appearances seem to be mostly based on their almost identical DNA. Yet, their personalities differed. One was a runner, whereas the other was a bodybuilder, so they had different body types. Their personality influenced their physiology. This idea is proven to be fairly strong because it happened naturally for the Jim twins. They were naturally separated at birth and led very similar lives but never communicated until their first meeting.
ReplyDeleteThis form of “cloning” an individual to have an identical person is flawed on the basis of continuity. This experiment would not follow continuity, but rather it would follow a change. Defining identical twins: “Even though identical twins have the same DNA, it can be expressed in different ways. The environment that the twins are exposed to(in the womb or out of the womb) determine fine physical characteristics. As a result, identical twins usually have different fingerprints. Also, as identical twins get older, more differences generally develop” (http://www.twin.com/identical/). The environment plays a major role in developing separated twins. If it was possible to make the twins develop in exactly identical environments, yes, identical humans could exist; but, this practice is largely impossible because there are too many environmental factors acting on a person. Campbell also agrees when speaking about factors in the womb, “Epigenetic variations might help explain why one identical twin acquires a genetically based disease...but the other does not” (358). The environment plays too big a role in shaping a human to not affect two people in different ways.
On the basis of if it is morally wrong to conduct such an experiment: yes it is. One cannot simply separate two identical twins and keep them in controlled environments for part of their life. This breaks many bioethical points, such as human subjects protection. This experiment would have no respect for human dignity or privacy. Humans should not have to subject themselves to an involuntary experiment if it affects their lives.
Josh LeVay (blevay@comcast.net)