Cloning question - 13
13) Who can be benefitted by human clones?india Updated: Jan 06, 2003 16:13 IST
Q. What is cloning?
A.Cloning is a scientific technique to create genetically identical molecules, cells or organisms.
Q. What are stem cells and what kind of research is being done on them?
A. Stem cells are special cells that haveyet to reach a stage of maturity when
they can perform specialised function (e.g. skin, heart or nerve cells); andtheycan, under circumstances, develop into many different types of cells.
Q. What is an embryo?
A. When a sperm fuses an egg, an embryo is formed.
Q. How is cloning done?
A. Cloning is possible either byembryo splitting or by nuclear transfer. InEmbryo splittingan early human embryo is split into two or more parts. Each part has the potential to develop into a complete cell (blastoclyst),which if implanted can develop into a child.However, this technniquecancreate only a limited number of cloned individuals because anembryo in itsearly stages can be separated only a limited number of times.
The other technique to clone is somatic cell nuclear transfer. In thisprocess the egg's nuclear material is removed anda somatic cell nucleus isinserted into that enucleated egg via microinjection or electro fusion. Thenthe resulting reconstituted cell has the potential to divide into a blastocyst,and if implanted, can develop into a child genetically identical to the nucleardonor.
Q. Are there different types of cloning techniques?
A. Yes. There are basically two types of cloning - therapeutic and reproductivecloning.
Q. What is therapeutic cloning?
A. Therapeutic cloning is the production of cloned cells to produce tissues and/or organs, mainly to improve healthcare. In the case of human cloning, applications of therapeutic cloning include the production of human therapeutic proteins, replacement tissues and organs, and cell-based therapies for curing diseases where there is cell damage.Once specialized cells can be derived from cloned embryos the following diseases can be treated:
• Brain disorders such as Parkinson and Alzheimer
• Spinal cord damage
• Autoimmune disorders such as multiple sclerosis and rheumatoid arthritis
Therapeutic cloning can provide genetically 100 per cent compatible organs such as livers and kidneys, and therefore, save the lives of those who would perish without it.
Q. What is reproductive cloning?
A. Reproductive cloning represents a new reproduction technique by which life can be given to an identical twin of the original cell donor. It is done by taking a woman's egg, removing the egg's nuclear material and replacing it with the nucleus of the donor, who wish to create his clone. Eventually, this replacement of the cloned embryo intothewomb of a mother leads topregnancy and the creation of a clone.
Reproductive cloning of animals is sometimes advocated for technology and farming, as well as forcloning endangered animals.Reproductive human cloning gives life to a new human being.
Until recently, only sexual reproduction or artificial reproduction techniques e.g. IVF existed.Reproductive human cloning will help:
• Childless couples who cannot have children even after years of infertility
• Homosexuals who cannot have a child that is 100% related to themgenetically
• Families who lost a beloved relative who might want same genetic codewho has died at an early age for example.
Q. What is the cloning process?
A. The process to clone is highly sensitive and demands a meticulous time management. Following are the steps of cloning:
§ The nucleus of the egg is removed and and replaced by a nucleus fromanother person's somatic cells. Then cell is then electrified to get fertilized
§ The fertilized egg develops into a mass of cells called the blastulaor blastoclyst
§ The blastoclyst then divides like a normal egg; first into two cells and then
into four cells and so on
§The natural protective layer of the cell is removed
§ The egg is implanted into a mother's womb
§The baby born will be a clone of the person whogave the nucleus to the egg
Q. Is clone an exact copy of the original?
A. A clone is a genetically identical twin of the donor of the nucleus. Between the clone and the original, only the gene structure will be similar.However, there are other factors, such as environment and a person's experiences,that help in shaping one’s personality and decide individual traits. In the case of cloning, only 99 per cent of those genes get re-created becauseone per centof such a child's genes would come from those in the egg.
Q. What is the difference between clones and naturally born individuals?
A. In simple terms, cloning means asexual or one parent reproduction. It is a form of reproduction in which the new being is a genetically identical copy, or a clone, of its parent.
In sexual reproduction eggs and sperms from the two parents merge and form a new individual, genetically similar but not identical to either parent.Scientists believe that single parent reproduction is the fastest and cheapest way for an organism to make new members of its kind, members that are proven to be adapted to the same environment as the successful parent.
On the other hand, in sexually produced offspring the genetic material has undergone recombination, and the new individuals produced may have different strengths and weaknesses than their parents.
Q. What is the brief history of cloning and why was it first introduced?
A. Nuclear transfer was first used in 1952 to study early development in frogs.
In the 1980's, the technique was used to clone cattle and sheep, using cells taken directly from early embryos.
In 1996, Dolly, the first animal was cloned from a differentiated somatic cell taken from an adult animal. In August 1998, more than 50 mice were cloned by nuclear transfer. Since then, the cloning of cattle, sheep, mice, goats and pigs have been reported.
1998 onwards different teams have claimed to have attempted human clones, with Dr Brigette finally winning the race.
Q. Who can be benefited by human clones?
A. The people who have lost a loved one might wish to keep that person’s "genome" alive.Childless couples and individuals who can't have children via in vitro fertilisation (or due to being homosexual) might wish to have theirchildren, and not ones genetically related to sperm or egg donors. Moreover, individuals or couples who wish to have a child via this technology might do it for their own reasons, as is their fundamental human right.
First Published: Dec 27, 2002 13:12 IST