Diana Ivanovaitė
Introduction
In this summary I
will analyse cloning in biotechnology - its meaning, the process of cloning,
different types of it and its effect on our society.
The key terms
Clones
- organisms that are exact
genetic copies. Every single bit of their DNA is identical.
DNA
- deoxyribonucleic acid: the chemical,
present at the centre of the cells of living things that control the structure
and purpose of each cell and carries genetic information during reproduction
Gene
- a part of the DNA in a cell that
controls the physical development, behaviour, etc. of an individual plant or
animal and is passed on from its parents.
Transgenic - of, relating to, or containing a gene or genes
transferred from another species.
Cell
- the smallest basic unit of a
plant or animal.
Embryo - an early stage of development of a multicellular
diploid eukaryotic organism.
Summary
Clones can happen
naturally—identical twins are just one of many examples. Also, they can be made
in the laboratory. There are two ways to make an exact genetic copy of an
organism in a lab: artificial embryo twinning
and somatic cell nuclear transfer.
Artificial
embryo twinning
A very early
embryo is separated into individual cells, which are allowed to divide and develop
for a short time in the Petri dish. The embryos are then placed into a
surrogate mother, where they finish developing. Again, since all the embryos
came from the same fertilized egg, they are genetically identical.
SCNT (somatic
cell nuclear transfer)
Somatic
cell: A somatic cell
is any cell in the body other than reproductive cells.
Nuclear: The nucleus is a compartment that holds the cell's
DNA.
Transfer: Moving an object from one place to another.
Difference
between gene cloning and organism cloning.
When scientists
clone an organism, they make an exact
genetic copy of the whole organism, as described above.
When scientists
clone a gene, they isolate and make exact
copies of just one of an organism's genes. Cloning a gene usually involves
copying the DNA sequence of that gene into a smaller, more easily manipulated
piece of DNA, such as a plasmid. This process makes it easier to study the
function of the individual gene in the laboratory.
Examples of
cloning
The first animal
to be successfully cloned was a sheep named Dolly, who was born in 1996. So far
cattle, chickens, dogs, cats, horses and several other mammals have been
cloned. Japanese scientists have even announced efforts to clone a wooly
mammoth. Wooly mammoths went extinct around 10,000 years ago. Global warming
has caused thawing in permafrost regions in eastern Russia, and recently the
remains of several well-preserved mammoths have been found. However, for
cloning to work, the mammoth DNA will need to be in near-perfect condition.
Despite several
highly publicized claims, human cloning still appears to be fiction. There
currently is no solid scientific evidence that anyone has cloned human embryos.
References
