We often associate human cloning with science fiction, beside technologies such as hoverboards and jetpacks or with the dystopian futures we find in The Island, Cloud Atlas and Brave New World. What would you say if I said you could meet a living, breathing human clone today? In modern discourse a clone is simply an exact copy. In the same way that a conman can clone my credit card and steal my money, scientists can create a clone of a living individual that is a genetically exact copy. The idea of cloning, especially human clones, scares a lot of people but genetic ‘copies’ already appear regularly in nature. Want to meet some human clones? Just find a pair of identical twins.
Identical, or monozygotic (MZ), twins are two individuals both descended from the same zygote (sperm + egg = zygote). Human MZ twins are produced when a zygote splits into two when just 16 cells large, sometimes the zygote will not divide completely and this will produce a pair of conjoined twins. MZ twins are genetically identical because they were once the same individual. Scientists can produce clones artificially. Cloning by nuclear transfer has created individuals such as Dolly the Sheep in 1996 by a team of scientists working at the Roslin Institute in Scotland. Cloned from a mammary gland (part of the female breast) cell, and named after Dolly Parton, Dolly was the first mammal to be successfully cloned.
How was Dolly created?
First, choose an individual to be cloned. This individual becomes the mammary gland cell donor. Starve the cells from the donor of nutrients, this stops the cell cycle and wipes the slate clean for the cell to specialise into any type of cell (called totipotence). Source an egg cell donor, throw away the cell nucleus, and mix thoroughly (fuse) with the semistarved totipotent cells. The nucleus from the mammary cell donor should now be contained inside the egg. Grow until cell division starts and an early embryo is formed. Implant the embryo into the uterus of a surrogate mother. Leave for the normal length of pregnancy.
Scientists have hoped to apply the process of nuclear transfer to human cloning. In 2005, South Korean scientist Dr Hwang Woo-suk claimed to have cloned human embryos to the blastocyst phase (an early stage of pregnancy). Scientists had only previously succeeded in stimulating a few early cell divisions. Dr Woo-Suk later retracted his claim, after admitting fabricating his results. Currently, human cloning trials have been unsuccessful, with some scientists suggesting the way the egg cells in primates divide once fertilised is to blame.
Plant and animal cloning have the potential to benefit society. The ability to clone crops and cattle that are known to produce high yields or have desirable characteristics has huge implications for agriculture, as cloning improves the control over selective breeding. Human cloning has the potential to revolutionise medicine, by creating an alternative means of reproduction for people with fertility problems, and alleviating the need for organ donation. It can be argued cloning is a genuine innovation.
Sanctity of Life
This raises several ethical and religious questions: when do we start playing God? Would a human clone have a soul? Religious believers talk about the ‘sanctity of life’, arguing that life’s divine origin means we should not interfere with it. There are also scientific issues to consider. How can scientists ensure safety and dignity in human trials?
Recently, claims milk and meat from cloned cattle were being sold in the UK caused a scandal. Despite the Food Standards Agency assurances this posed no safety risk, some have argued that GM (Genetically Modified) foods are unsafe. Creating genetically identical individuals leaves a population at greater risk from disease, and without sexual reproduction and variation the process of evolution would not occur at its current rate.
Cloning is indeed an innovation, proof that scientists can make science fiction fact
Some animals created by cloning have experienced many health issues. Dolly was euthanized aged six (most sheep have a life expectancy of 11-12 years) after exhibiting lung problems usually only found in far older sheep; although there is no definitive proof this was because of her unusual origin, similar problems have been found in cloned mice; suggesting some clones are not as fit as their sexually produced counterparts.
The process of artificial cloning is still developing, and there are good arguments for and against its continuation. Cloning is indeed an innovation, proof that scientists can make science fiction fact, but the area is surrounded in ethical doubt, and without the correct regulation maybe cloning could go too far.