In biology, cloning is the process of producing similar populations of genetically identical individuals that occurs in nature when organisms such as bacteria, insects, plants or animals reproduce asexually.
What do you think of when you hear the word 'cloning'? Everybody usually think it means to make an exact replica of one or other organism, like Dolly the sheep. Dolly was cloned from another sheep's DNA and grew in the womb of a surrogate sheep. This type of cloning we call reproductive cloning.
Human/animal cloning is the creation of a genetically copy of a human/animal. The term is generally used to refer to artificial human/animal cloning, which is the reproduction of human cells and tissue.
Lets have a look at when Dolly became a sheep. First the scientists took an egg cell/ovum and removed all the DNA from the cell. After that they took the DNA from a donor sheep and injected it into the ovum. The ovum now carried the DNA of the donor. This cell was then stimulated with chemicals or electricity to start cell division.
The cell was then placed in the womb of the surrogate sheep and developed in the womb and if everything goes according to plan the surrogate sheep will carry the lamb until birth. The clone will then be born as normal.
Usually we think a clone is the exact copy of the donor who gave the DNA, but that is not true. A clone is only identical to the donor as far as their chromosomes are the same. An individual consists of more than only chromosomes and that is why a clone, like an identical twin, are not exactly the same as the donor, even if they look the same.
According to the people who does reproductive cloning, you can use any cell and re-program it to make a whole organism. That means you can take a cell from any place on your body and program that cell in such a way that it can turn into a new human.
A lot of scientists warn us that faulty re-programming of cells can lead to deformities and can cause death.
In February 2003, Dolly was euthanized because she was suffering from arthritis and lung cancer. Dolly gave birth to 6 lambs during her live time.
If you look at statistics, cloning does not completely look so wonderful. Dolly was a clone of the 'Finn Dorset' sheep that only lived 6 years and the average age for these sheep are 11-12 years.
Dolly's illnesses shows us that we are not 100% informed of how our genes work, but it has come a far way.
If you look at the medical field, doctors and scientists are trying to clone organs that will help save the lives of their patients and then they do not have to wait for a suitable donor.
- There is a lot of debate around cloning - is it right or wrong. Everybody has an opinion. What do you think about the whole cloning process? Break it up into two categories - Cloning a human and cloning an organ.
- Explain the following words by looking up the meaning and then explaining it in your own words
- surrogate mother
- cell division
- In which other areas of life is cloning used (not only concerning plants and animals)