Me2 key objects
Dolly the sheep
What is it?
Dolly hit the headlines in 1997 as the first mammal cloned from an
adult cell.
She was born at the Roslin Institute just outside Edinburgh on 5
July 1996.
Background information
Dolly the sheep was
born in 1996. She became a celebrity because she was the first
mammal ever to be cloned using a cell from an adult animal.
In biology, a clone is any organism whose genetic information is
identical to that of a "mother organism" from which it was created.
Until Dolly most biologists thought cells from an adult creature
could not be used in cloning. The research was conducted at the
Roslin Institute, Edinburgh.
The terms clone and cloning have a few different meanings -
Dolly was produced using a technique called Nuclear Transfer (NT)
or cell nuclear replacement (CNR). Cells from the udder of a 6-year
old Finn Dorset ewe were cultured for several weeks in the
laboratory.
The genetic material in an unfertilised egg was then replaced
with individual cells from this culture. Of the 277 reconstructed
eggs, 29 appeared to develop normally to the blastocyst stage (a
fertilized egg after several days of cell division).
They were then implanted into surrogate Scottish Blackface ewes.
148 days later, one pregnancy gave rise to a live lamb - Dolly.
Me2 key interactives
You are unique
What is it?
In this computer interactive you can find out what makes you
different from everyone else.
Background information
Humans have 46 chromosomes - 23 from your father and 23 from your
mother. The chromosomes inherited from your parents pair up to form
23 paired chromosomes and carry all the genetic information needed
to make you.
Each paired chromosome is composed of two tightly coiled strands
of DNA (deoxyribonucleic acid) that joins in the middle to form an
X shape.
These strands of DNA have sections called genes, which contain
the information that determines the growth, functioning and
characteristics of the host organism.
Variation is present in every species. Humans have similar
characteristics, such as hair, legs and eyes, and characteristics
that are different, such as hair colour and eye colour.
No two individuals are exactly the same. Even identical twins
who come from the same fertilised egg and share the same common
genetic characteristics have different environmental
characteristics, resulting from their living conditions,etc.
Variations can be either inherited (passed on genetically from
the parents) or are a result of environmental differences.
Continuous variation is controlled by genes (inherited factors)
and in a population can be caused not only by multiple genetic
factors, but also the environment, e.g. availability of food.
Height and mass are common characteristics showing continuous
variation.
The environment has no effect on discontinuous variation. There
is no pattern in a population, but instead marked changes between
two or more extremes. Eye colour and ear lobe type are human
characteristics showing discontinuous variation. Sudden inherited
changes caused by mutations are also examples of discontinuous
variation.
Learning outcomes
- We all have a unique set of characteristics linked to tiny
differences in our DNA.
- Characteristics like our gender, hair colour, eye colour,
tongue rolling, ear lobes, right or left handedness and skin colour
are controlled by our DNA.
Spot the clone
What is it?
Can you spot the clone? In this computer interactive, you need to
use clues that define a clone and to decide if a series of
different animals or plants are clones or not.
Background information
Scientists now have the power to understand the building blocks of
life (genes) and manipulate them using genetic engineering. It’s up
to us to decide how these powers should be used.
In biology, a clone is any organism whose genetic information is
identical to that of a "mother organism" from which it was created.
Some clones exist in nature. Others are created by scientists.
In botany and horticulture, a clone is an individual plant
produced from a mother plant by some form of vegetative
reproduction. Cloning an organism means creating a new organism
with the same genetic information as an existing one.
In a modern context, this can involve somatic cell (any cell
except reproductive cells e.g. sperm) nuclear transfer in which the
nucleus is removed from an egg cell and replaced with a nucleus
extracted from a cell of the organism to be cloned (currently, both
the egg cell and its transplanted nucleus must be from the same
species).
As the nucleus contains (almost) all of the genetic information
of a lifeform, the "host" egg cell will develop into an organism
genetically identical to the nucleus "donor". Mitochondrial DNA
(DNA found in the structures inside cells that act as power
plants), which is not transferred by this process, is generally
ignored as its effects on organisms are thought to be relatively
minor.
Identical twins are genetically identical but not generally
considered to be ‘clones’ as one is not the parent of the other.
However, genetically they are exactly the same as clones would
be.
The term clone is used in horticulture to mean all descendants
of a single plant, produced by vegetative reproduction. Many
horticultural varieties of plants are clones, having been derived
from a single individual, multiplied by some process other than
sexual reproduction.
As an example, some European varieties of grapes represent
clones that have been propagated for over two millennia. This is a
genuine example of cloning in the broader biological sense, as it
creates genetically identical organisms by biological means.
Learning outcomes
- A clone is a living thing that is genetically identical to
another living thing.
- Some clones do exist in nature but to produce a clone like
dolly who is genetically identical to her "mother" sheep involves
complicated scientific research.
Design a GM crop
What is it?
In this computer interactive, you can explore the pros and cons of
genetic modification (GM) and think about how you feel about the
different ways in which GM technology should or should not be used.
See how your ideas compare with other visitors.
Background information
For years humans have been breeding animals and plants to get the
characteristics they desire, for example high yielding species. Two
techniques used to do this are selective breeding (breeding animals
and plants by controlling the environment) and cross-breeding
(breeding species with the same ancestors).
Different crops and animals such as potatoes and chickens have
been selectively bred in this way.
Now that scientists understand the building blocks of life
(genes) they can manipulate characteristics through genetic
modification (GM). Genes (sections of DNA molecules) contain the
information that determines the characteristics of organisms and
plants.
To obtain the characteristics they desire, scientists cut the
required genetic information out of the DNA of one organism and
insert it into the organism they are modifying, creating a new
genetically modified or genetically engineered organism.
Unlike breeding, with this technology genes from animals can be
inserted into plants and vice versa. Transgenic organisms are
created when genes from foreign organisms are inserted into the DNA
of the genetically engineered organisms.
Currently the advantages and disadvantages of this technique are
being investigated and debated. Although GM tomatoes first appeared
on British supermarket shelves in 1996, the technology was not
brought into the public eye until August 1998 when a controversial
study was published which suggested that some strains of GM
potatoes might be toxic to laboratory rats. The debate continues
and it is up to us to decide how to progress the technology.
Learning outcomes
- Genetic modification (GM) can be used for many different
purposes.
- There are arguments for and against using GM.
- We should each decide for ourselves, based on the evidence,
what types of genetic modification we support.
Vote on cloning
What is it?
Through this computer
interactive, you can explore the different ways in which cloning
technology could be used and vote on which types of cloning should/
should not be allowed.
Background information
A clone is a living thing that has exactly the same genes as
another living thing. Cloning could be used for medical treatments
or for farming. It’s up to us to decide as a society how we want
scientists to use genetic engineering for cloning purposes.
At present human cloning isn't feasible - it has not yet been
perfected.
There are two potential arguments in favour of human
cloning:
Human ‘therapeutic’ cloning: therapeutic cloning means using
cloning to find treatments for diseases such as Alzheimer’s and
Parkinson’s. A patient’s own cells are used to produce a
genetically identical embryo. After about a week the development of
the embryo is stopped and the cells are used for the treatment.
Human reproductive cloning: the same process that is used for
therapeutic cloning could be used to create a baby. If the
developing embryo was placed in a woman’s womb, it might be able to
grow and be born naturally.
Many people find the use of embryos in research controversial.
The Human Fertilisation & Embryology Authority (HETA) have
responsibility for licensing and monitoring all human embryo
research in the UK.
Learning outcomes
- Tthere are many potential uses for cloning techniques in both
humans and animals.
- Some are potentially very beneficial and some are less
beneficial. Some people object to all uses of cloning, some people
to only some uses.
- We must each decide individually what we think is acceptable
then we must decide as a society.