©2000 Timothy G. Standish Psalm 8:4-7 4What is man that thou art mindful of him:” and the son of...
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Transcript of ©2000 Timothy G. Standish Psalm 8:4-7 4What is man that thou art mindful of him:” and the son of...
©2000 Timothy G. Standish
Psalm 8:4-74 What is man that thou art mindful of him:” and the
son of man, that thou visitest him?5 For thou hast made him a little lower than the angels,
and hast crowned him with glory and honour.6 Thou madest him to have dominion over the works
of thy hands; thou hast put all things under his feet:7 All sheep and oxen, yea, and the beasts of the field;
©2000 Timothy G. Standish
Cloning For Cloning For Every ManEvery Man
Timothy G. Standish, Ph.D.
©2000 Timothy G. Standish
“The cloning of mammals . . . is biologically impossible.”
James McGrath and Davor SolterScience, Dec. 14, 1984
©2000 Timothy G. Standish
“Our announcement of Dolly’s birth in February 1997 attracted enormous press interest, perhaps because Dolly drew attention to the possibility of cloning humans. This is an outcome I hope never comes to pass.”
Ian WilmutScientific American, December, 1998
©2000 Timothy G. Standish
What This Talk Is AboutWhat This Talk Is About
Four Questions:Four Questions: What is cloning? How is cloning achieved? Why Clone? Why would anyone want to
clone an animal or human? Ethical Considerations? Why should cloning
technology be carefully thought through before being widely used and particularly before humans should be cloned?
©2000 Timothy G. Standish
System
The Code For LifeThe Code For Life
Organism
Organ
Tissues
Cell
.
Nucleus
©2000 Timothy G. Standish
Nucleus
The Code For LifeThe Code For Life
Chromosome
Genes
Brown eyes
Straight hair
Big nose
©2000 Timothy G. Standish
The Nucleus Contains An The Nucleus Contains An Organism’s BlueprintOrganism’s Blueprint
Every cell has a nucleus when it is made Within every nucleus is a complete copy of
the organism’s genetic information Differences between cells result from
different genes being “expressed” in different ways
©2000 Timothy G. Standish
ClonesClones Clones are two genetically identical organisms Nature commonly produces clones Most bacteria reproduce by “binary fission” in which
the mother cell splits in two with a complete copy of the genetic information being passed to each daughter cell
Many single-celled eukaryotic organisms reproduce in a similar way
In higher organisms, clones also occur naturally, but usually through some more complex mechanism
©2000 Timothy G. Standish
Plant ClonesPlant Clones
Any time that plants are reproduced using cuttings, to produce new separate plants, they are being cloned
Many commercially important strains of fruits are produced from clones
Seedless plants can only be reproduced as clones
©2000 Timothy G. Standish
Animal ClonesAnimal Clones
Budding is common in corals and some other animals Some vertebrates reproduce via parthenogenesis
Animal clones may result from “budding” as a way of reproducing
©2000 Timothy G. Standish
Natural Human ClonesNatural Human Clones
This happens naturally in about 3/1,000 births Identical twins are genetically identical because they have identical genes in their nucleus This does not mean they are truly identical
Identical twins result from the splitting of an embryo into two separate cell masses which both go on to develop into genetically identical twins
©2000 Timothy G. Standish
How Is Cloning Done?How Is Cloning Done?
Making a clone is, in theory, a very simple thing
All one has to do is take a cell with the nucleus of the organism you want to clone, and grow it into a new organism
The difficulty is that most cells do not readily grow into whole new organisms
©2000 Timothy G. Standish
Barriers To Cloning MammalsBarriers To Cloning Mammals Most cells seem to have a limit to how many times they will
divide (the Hayflick limit) A complex interplay between nucleus and cytoplasm exists
that prevents most cells from producing cells other than their own type
During development, cells differentiate into all the cell types in the body, but they do not readily go back to being undifferentiated
The egg and a few early cells in an embryo are the only cells capable of developing all the cell types necessary to make a whole mammal
©2000 Timothy G. Standish
Overcoming The Barriers Overcoming The Barriers
A nucleus needs the right cytoplasm environment if it is to become “totipotent”
Eggs provide the correct environment
The nucleus must be “reset” so that it forgets it was in a differentiated cell
Ian Wilmut learned that starving cells in culture resets their nucleus
Cells developing from mammal eggs do not seem to have a limit to the number of times they will divide
©2000 Timothy G. Standish
Making A CloneMaking A CloneThe method for making a clone used by Ian Wilmut
includes 6 steps:
1 Production of quiescent cells containing nuclei that “forget” the type of cell they are in
2 Collection of the donor nucleus
3 Preparation of an egg lacking genetic material
4 Insertion of the donor nucleus
5 Initiation of development
6 Development of the embryo in a surrogate mother
©2000 Timothy G. Standish
How Ian Wilmut Made Dolly 1How Ian Wilmut Made Dolly 1Making Quiescent CellsMaking Quiescent Cells
Finn Dorset ewe3.5 months pregnant
Mammary gland cells
Culture mammary cells
Harvest quiescent cells
Starve cells
©2000 Timothy G. Standish
Suction
Suction Pipette
Glass pipette
How Ian Wilmut Made Dolly 2How Ian Wilmut Made Dolly 2Collecting The Donor NucleusCollecting The Donor Nucleus
©2000 Timothy G. Standish
Suction
Suction Pipette
Glass pipette
How Ian Wilmut Made Dolly 2How Ian Wilmut Made Dolly 2Collecting The Donor NucleusCollecting The Donor Nucleus
©2000 Timothy G. Standish
How Ian Wilmut Made Dolly 3How Ian Wilmut Made Dolly 3Egg PreparationEgg Preparation
Scottish Blackfaced ewe egg donor
An egg is collected then placed into a dish where it can be manipulated
Egg
©2000 Timothy G. Standish
Suction
Suction Pipette
Glass pipette
EggChromosomes
How Ian Wilmut Made Dolly 3How Ian Wilmut Made Dolly 3Egg PreparationEgg Preparation
©2000 Timothy G. Standish
Egg
Suction
Suction Pipette
Glass pipetteChromosomes
How Ian Wilmut Made Dolly 3How Ian Wilmut Made Dolly 3Egg PreparationEgg Preparation
©2000 Timothy G. Standish
Suction
Suction Pipette
Glass pipette
How Ian Wilmut Made Dolly 4How Ian Wilmut Made Dolly 4Inserting The Donor NucleusInserting The Donor Nucleus
©2000 Timothy G. Standish
Suction
Suction Pipette
Glass pipette
How Ian Wilmut Made Dolly 4How Ian Wilmut Made Dolly 4Inserting The Donor NucleusInserting The Donor Nucleus
©2000 Timothy G. Standish
Suction
Suction Pipette
How Ian Wilmut Made Dolly 4How Ian Wilmut Made Dolly 4Inserting The Donor NucleusInserting The Donor Nucleus
©2000 Timothy G. Standish
How Ian Wilmut Made Dolly 5How Ian Wilmut Made Dolly 5Initiating DevelopmentInitiating Development
©2000 Timothy G. Standish
Zygote
How Ian Wilmut Made Dolly 5How Ian Wilmut Made Dolly 5Initiating DevelopmentInitiating Development
©2000 Timothy G. Standish
Cleavage
How Ian Wilmut Made Dolly 5How Ian Wilmut Made Dolly 5Initiating DevelopmentInitiating Development
©2000 Timothy G. Standish
Cleavage
How Ian Wilmut Made Dolly 5How Ian Wilmut Made Dolly 5Initiating DevelopmentInitiating Development
©2000 Timothy G. Standish
Cleavage
How Ian Wilmut Made Dolly 5How Ian Wilmut Made Dolly 5Initiating DevelopmentInitiating Development
©2000 Timothy G. Standish
Cleavage
How Ian Wilmut Made Dolly 5How Ian Wilmut Made Dolly 5Initiating DevelopmentInitiating Development
©2000 Timothy G. Standish
Morula
How Ian Wilmut Made Dolly 5How Ian Wilmut Made Dolly 5Initiating DevelopmentInitiating Development
©2000 Timothy G. Standish
Scottish Blackfaced ewe surrogate
mother
How Ian Wilmut Made Dolly 6How Ian Wilmut Made Dolly 6DevelopmentDevelopment
Morula
Finn Dorset lambDolly
©2000 Timothy G. Standish
Why Clone?Why Clone?Cloning provides opportunities in four major areas
1 Study of developmentProduction of genetically identical organisms that can be studied
in different environments has the potential to dramatically advance our understanding of development
2 Propagation of valuable organisms
3 Control over reproduction
4 Production of recombinant organisms
5 Production of engineered organs
©2000 Timothy G. Standish
Propagation Of Valuable OrganismsPropagation Of Valuable Organisms
There are limits to the possibility of reproducing valuable combinations of traits using traditional breeding techniques
For example, race horses are regularly bred to produce fast offspring, but occasionally an excellent combination of traits is produced that cannot be repeated even when the same parents are used
Cloning could produce many copies of Pharlap or other valuable horses
©2000 Timothy G. Standish
Control Over ReproductionControl Over Reproduction
Production of a clone allows very precise predictions about the results of a pregnancy
Cloning offers the potential to produce genetically related offspring from sterile organisms
Before cloning, cells can be engineered to remove genetic defects, or introduce desired traits
©2000 Timothy G. Standish
Production OfProduction OfRecombinant OrganismsRecombinant Organisms
Cloned organisms can be made from cultured cells It is relatively easy to introduce new genes into cell
cultures Cells from recombinant cell cultures can be used as
nucleus donors for clone production This technique has already been used by researchers
at the Roslin Institute to produce recombinant sheep that make human factor IX
Factor IX is used to treat hemophilia B
©2000 Timothy G. Standish
Production Of Engineered OrgansProduction Of Engineered Organs
The potential exists to engineer organisms that produce organs which will not be rejected when introduced into humans or other needy recipients
To do this, animals would be produced that do not make the proteins and other chemicals on cell surfaces that tell the immune system they do not belong in a human body
©2000 Timothy G. Standish
Why Clone Humans?Why Clone Humans?
Production of genetically related offspring by infertile couples for whom other reproductive technologies have failed
Narcissism Replacement of lost loved ones Production of genetically “improved” humans
(custom-built babies) Production of spare parts for those needing
replacement organs
©2000 Timothy G. Standish
Ethical ConsiderationsEthical Considerations
All new technologies have unforeseen effects. We cannot expect that cloning will be without unexpected benefits and problems
Is any reproductive technology tampering with the way God made nature to work?
Are we “playing God” when we create organisms “designed” by humans?
Will there be abuses of the ability to produce engineered organisms . . . ?
©2000 Timothy G. Standish
Production of large numbers of clones would lower genetic diversity
Cloning technology makes other technologies more practical:
Production of cloned body parts requires the production of embryos that are then used as a source of stem cells
Ethical ConsiderationsEthical Considerations
©2000 Timothy G. Standish
The Ethics Of Human CloningThe Ethics Of Human Cloning Would cloning be in the best interest of the child?
– How would a child react to knowing how they will develop in the future?
– What expectations would society put on cloned children? Is it ethical to produce a life/potential life for the
purpose of saving or enhancing the life of a living person?
Is producing a clone as a source of stem cells, then discarding the remaining parts, equivalent to abortion?
©2000 Timothy G. Standish
Who Owns A Person’s Who Owns A Person’s Genetic Potential?Genetic Potential?
It would be immoral to take the gametes of a person and, without their consent, use them to produce offspring
Cloning offers the potential of making genetic copies of anyone -- With or without their consent
©2000 Timothy G. Standish
Cloning and ReligionCloning and Religion At least one religious group, Raeliens, believe
that cloning is the secret to immortality Raeliens believe that life on earth was created
by aliens using genetic engineering Clonaid, purported to be the first company
dedicated to human cloning, was founded in February 1997 by Rael, leader of the Raeliens, and a group of investors
Clonaid is run by a corporation in the Bahamas called Valiant Venture Ltd
©2000 Timothy G. Standish
Recent Developments In CloningRecent Developments In Cloning 1999 - A number of cloned cows and other organisms have died
without explanation. In general clones are less healthy than offspring produced using other methods (Lancet, U.S. News and World Report, May 24, 1999)
Dolly has chromosomes with telomeres shorter than those of other ewes her age. Dolly’s lambs have telomeres that are normal in length for sheep their age (Nature, May 27, 1999)
The first male has been cloned from adult cells, named Fibro by Yanagimachi’s group in Hawaii, cells from an adult mouse tail were used as the source of 274 nuclei, one of which developed to adulthood and fathered two normal litters (Nature Genetics, 22:127-128, June 1999)
©2000 Timothy G. Standish
Recent Developments In CloningRecent Developments In Cloning 1998 Nov. - Plans for cloning humans on a commercial basis are
announced (http://www.clonaid.com/) 1999 - Discovery of a frozen woolly mammoth in Siberia has presented
the possibility of cloning mammoths using a mammoth nucleus and elephant eggs (http://cnn.com/NATURE/9907/23/mammoth.reut/)
1999 - A group in New Zealand has approved the cloning of the extinct Hula bird using preserved materials (http://cnn.com/NATURE/9907/20/cloning.enn/)
1999 - Dolly is shown to have different mtDNA than the eue from whom she was cloned, but the same mtDNA as the mother who donated the egg (Eric Schon, Ian Wilmut et al. September 1999 Nature Genetics)
©2000 Timothy G. Standish
Cloning Humans Using Cow EggsCloning Humans Using Cow Eggs June 17, 1999 American Cell Technology (ACT) announce they
had made a human clone during November 1998 The clone was made by inserting a human nucleus from skin on
a man’s leg into an enucleated cow’s egg After developing for 14 days the clone was destroyed
(Researches said before 14 days it “was not human”) Clones of this type may be potential sources of stem cells and
perfect tissue matches for those needing transplants
According to the BBC, Lord Robert Winston, a British fertility expert, said the research was "totally ethical”– This information came from the BBC web page
news.bbc.co.uk/hi/english/sci/tech/newsid_371000/371378.stmThe first documented human clone
©2000 Timothy G. Standish
“But if there was one sin above another which called for the destruction of the race by the flood, it was the base crime of amalgamation of man and beast which defaced the image of God, and caused confusion everywhere.”
Ellen G. WhiteSpiritual Gifts. Vol. 3, p 64
©2000 Timothy G. Standish
Recent Developments In CloningRecent Developments In Cloning 2000 - In August the British government releases a report
calling for approval of human cloning for research purposes with the objective of harvesting stem cells for therapeutic purposes.
2000 - August, two groups report cloning pigs. This technology may ultimately lead to successful xenotransplantation.
2001 - January, Noah, a gaur, the first successfully cloned endangered species, dies of dysentery two days after birth
2001 - The British House of Lords approves legislation taking effect January 31 that allows human cloning
2001 - Dr. Severino Antinori announces plans to clone a human within a year
©2000 Timothy G. Standish
Psalm 8:4-74 What is man that thou art mindful of him:” and the
son of man, that thou visitest him?5 For thou hast made him a little lower than the angels,
and hast crowned him with glory and honour.6 Thou madest him to have dominion over the works
of thy hands; thou hast put all things under his feet:7 All sheep and oxen, yea, and the beasts of the field;
©2000 Timothy G. Standish
“None of the suggested uses of cloning for making copies of existing people is ethically acceptable to my way of thinking.”
Ian WilmutScientific American, December, 1998
©2000 Timothy G. Standish
Not Genetics AloneNot Genetics AloneTo be a human person means more than
having a human genome, it means having a narrative identity of one's own. Likewise, membership in the human family involves a rich nexus of cultural links that cannot be reduced to taxonomy. On the question of human nature, we need a philosophical fresh start that cannot be provided by genomics alone.
Alex Mauron. 2001. ESSAYS ON SCIENCE AND SOCIETY: Is the Genome the Secular Equivalent of the Soul? Science 291:831-832.
©2000 Timothy G. Standish