What is cloning? Are there different types of cloning?
Cloning is the creation of an organism that is an exact genetic copy of another. There are different types of cloning. A basic understanding of the different types of cloning is key to taking an informed stance on current public policy issues and making the best possible personal decisions.
The following 3 types of cloning technologies (1) recombinant DNA technology or DNA cloning, (2) reproductive cloning, and (3) therapeutic cloning.
What is a Clone ?
As per biology, a clone is a cell or an organism that is genetically identical to another cell or organism. Many simple organisms such as bacteria reproduce themselves by copying their DNA and splitting in half.
The two bacteria that result from this form of asexual reproduction are genetically similar, they are clones of each other. In contrast, during the process of sexual reproduction, the nucleus of a sperm cell, which carries the father’s DNA, fuses with the nucleus of the egg cell, which contains the mother’s DNA. The resulting offspring carry genetic material from both parents and are not identical to either parent.
The verb “to clone” refers to the process of creating cloned cells or organisms. The process differs, depending on the kinds of cells used in the cloning procedure and the desired result. Usually, when scientists clone an animal, they take the nucleus of a cell — which contains chromosomes made of deoxyribonucleic acid (DNA) and proteins — and place it into an egg cell (also called an oocyte) from which the nucleus has been removed. The egg cell then divides to produce an embryo that develops into an animal, if the procedures work as planned.
Cloning an Animal vs Cloning a Gene
You’ve heard about cloning animals – sheep, mice, even house pets – in the news. From time to time, you may have also heard about researchers cloning, or identifying, genes that are responsible for various medical conditions or traits.
What is the difference?
Cloning an animal, or any other organism, refers to making an exact genetic copy of that organism.
Cloning a gene means isolating an exact copy of a single gene from the entire genome of an organism. Usually this involves copying the DNA sequence of that gene into a smaller, more accessible piece of DNA, such as a plasmid. This makes it easier to study the function of the individual gene in the laboratory.
Cloning of Dolly Celebrity Sheep Has Died at Age 6
Dolly ( A Sheep), the first mammal to be cloned from adult DNA, was put down by lethal injection Feb. 14, 2003. Dolly had been suffering from lung cancer and crippling arthritis. Although most Finn Dorset sheep live to be 11 to 12 years of age, postmortem examination of Dolly seemed to indicate that, other than her cancer and arthritis, she appeared to be quite normal. The unnamed sheep from which Dolly was cloned had died several years prior to her creation. Dolly was a mother to 6 lambs, bred the old-fashioned way.
Image credit: Roslin Institute Image Library, http://www.roslin.ac.uk/library/
Ethics & Cloning
Ethical issues are those that ask us to consider the potential moral outcomes of cloning technologies.
- Who has the right to have children, no matter how they are created? Who doesn’t? Why?
- Is human cloning “playing with nature?” If so, how does that compare with other reproductive technologies such as in vitro fertilization or hormone treatments?
- Does cloning to create stem cells, also called therapeutic cloning, justify destroying a human embryo? Why, or why not?
- If a clone originates from an existing person, who is the parent?
- What are some of the social challenges a cloned child might face?
- Do the benefits of human cloning outweigh the costs of human dignity?
- Should cloning research be regulated? How, and by whom?