43 Days of Life: Are Twins Clones?
Asking if identical twins are cloning might seem odd. However for years a now retired Member of Congress (who should have known better) would occasionally argue with unsuspecting pro-lifers that identical twins and cloning are similar enough that human cloning should not be as taboo as it is.
The word “clone” is not new, for over a century it was used to describe genetic twins it was only in the 1970’s that it was used for describing taking the DNA from an individual and making a new individual.
The Congressman was right to a certain extent. The closest we have to human clones today are monozygotic, or identical, twins. Their genetic makeup is only very similar, not actually identical. With identical twins, (or even rarer instances identical triplets) the fertilized egg once split in half and developed as two zygotes instead of one. Identical twins don’t have the same fingerprints, thanks to minute variations in womb pressures and amniotic fluid.
So how do human twins differ from clones? Curiousity.com has more:
Having a clone may seem like having an identical twin, except identical twins are born at the same time and cloning, by definition, would have to be done once a baby is born, if not at a later stage in life. Furthermore, once the clone is conceived, it would start its life as a fetus, not as an adult copy. Therefore, having a clone is more similar to having a child who is exactly like you, not an identical twin.
Identical twins’ DNA is not an identical match [source: American Journal of Human Genetics]. Slight genetic changes, called copy number variations, occur in the womb. With these variations, some coding is copied twice or is missing, so deep down at the genetic level, identical twins are not completely identical. Although a human clone would have exactly the same DNA as its host, it would still be capable of independent thoughts, feelings and interests, similar to identical twins. Furthermore, a human clone might grow up differently than the host because a variety of environmental factors and experiences work alongside genetics to mold a person’s development.
Sounds cool right? To have a genetic duplicate to do all your chores? FRC’s Dr. David Prentice has a few reasons why man should be careful playing God.
What’s wrong with human reproductive cloning?
The act of cloning in order to produce human beings replaces procreation with production. Human beings are treated as manufactured products rather than created persons. In animal cloning experiments, only 2 to 3 percent of all reproductive cloning attempts have been successful at producing born clones. The clones that are successfully birthed are often born with major disabilities or deformities, or experience problems after birth. For example, cloned mice have been shown to be extremely obese. Cloned cows usually experience lung and heart problems. Dolly the sheep – the first mammal ever to be cloned from an adult cell nucleus – experienced early onset arthritis and had a lung disease. Due to these complications, she was put down only six years after birth. Thus, the few cloned children that might manage to be born would be subjected to disabilities, deformities, and abnormally short lives, all because of the imprudent curiosity of some researchers. Reproductive cloning would allow a woman to clone herself using her own egg, her own somatic cell, and her own womb. Not only would a man be superfluous to the process of creating a child, but a woman would be giving birth to an individual who is both her identical twin sister and her child.
Cloning could even allow us to pick and choose desired physical and mental traits for our children. Characteristics such as height and intelligence could be manipulated according to someone else’s likes and dislikes. By purposely choosing desirable characteristics and avoiding undesirable ones for our future generations, scientists employ a method of eugenics. When contemplating the future of cloning, it is especially telling to hear Ian Wilmut, the creator of Dolly the sheep, describe human reproductive cloning as “criminally irresponsible.”
And a happy (day after) birthday to the “clones” in my family who celebrated their 51st birthday yesterday!