Cloning
One subject that has drawn a lot of attention to the ethics of embryo research and grabbed headline inches is Cloning.
Cloning in biological terms means reproducing a organism with same genetic information-this happens in nature for example with for bacteria. An identical twin for example can be considered a clone of its brother/sister.
But of cause in this sense of the word we mean the creation of an exact copy of a adult being.
There is a clear difference between reproductive technology such as vitro fertilization (IVF) and genetic technologies which try to change the genetic make-up of future organisms-but to the non-scientist these things seem to involve fiddling with nature to a greater or lesser extent.
This has no place in the treatment of infertility for cloning research, however, the cells used are often embryonic in origin.
Cloning will not produce a perfect copy. A clone will merely have the same genes as its father/mother/donor/forebear. Produced in a different womb and growing up at a different time than his forebear, a clone may (we don't know !) be much less similar than an identical twin.
But what is cloning?
Cloning is the construction of a cell or cells containing the DNA from one individual, bypassing the process of reproduction.
This occurs in nature with bacteria and higher organism (some species of snails, shrimp and amphibians).
Identical twins like clones have exactly the same genetic make-up, because they are derived from the same sperm and same oocyte.
The fertilized oocyte splits into two identical embryos, therefore having the same genetic material and sharing the same womb, being born simultaneously.
(Non-identical twins arise when two oocyte are released at ovulation instead of the usual one and are fertilised by two different spermatozoa).
How do we make clones?
The most common way is by "Nuclear Transfer" whereby the nuclear material of a cell (the DNA) is taken from one cell and placed in an oocyte that has had its own nucleus removed. Afterwards the fusion is completed by electric or chemical means.
Why was dolly so special?
It was the first mammal that was cloned from DNA from an adult animal. Earlier clones had been created from using cells from embryos (that have the ability to form other cells).
Importantly, cloning proved that cells can be re-programmed to form other cell types-which was previously believed only existed in some embryonic cells.What made Dolly the sheep different was that she was cloned from an udder cell of an adult sheep.
What are the dangers of cloning?
Warnings have been voiced from the very scientist that created the first clones.
The percentage of "constructed animals" that develop to birth is about 1%.
A great number of these have presented pulmonary, circularly and immune problems.
Fears-advantages-future
When the first successful organs transplants were announced outcries of new Frankensteins were to be heard.
Must we always look at new medical innovations as something bad?
The birth of Dolly proved a new found adaptability of the cell to return to its earliest developmental stage and means that maybe cells of one type can be re-programmed to form other types of cells. This would indeed be very important for many medical conditions.
Stem cells
When we talk about embryo research we usually confuse and refer to a specific type of cell called a Stem Cell.
These cells, like the cells used in cloning, can be re-programmed to form embryos. They can alter their “developmental fate” to become almost any other cell type in the body.
One concerns is from where these cells originate:
Although some types of stem cell are found in the adult body in very small quantities the majority (and the most useful type) are derived from an early stage of the embryo (the blastocyst).
The cells from the inner cell mass of these embryos under special culture conditions have the ability to form other types, making them very important for not only cloning but in transplantation and in the future, organ and tissue regeneration.
Therapeutic Cloning
If tissue can be regenerated, this could help people with Parkinson’s, Alzheimer’s and even diabetes. Also if it is possible to recreate nerve cells we may help sufferers of limb damage and spinal injury.
Modern genetic engineering may be hit and miss but far more effective.
A thorough bred horse or breed of dog can be considered a product of genetic manipulation. The process however took many generations to achieve its desired effect.
As opposed to the “guinea pigs”, cell lines and tissue cultures created and selected in the laboratory are cheaper, quicker and more ethical in reaching a desired end.
Can cloning be used to bring back dinosaurs?
The success of cloning is still too low but not impossible-tissue samples of the wholly mammoth have been found frozen for thousands of years.
Interestingly, for several years now, before the popularity of the book “Jurassic Park” The London Zoo has operated a “Frozen Zoo”. Animals faced with extinction have their embryos frozen. A female from a related species can be used in the future as a Surrogate.
