Transcript Cloning, Gene Therapy and Stem Cell Research

Cloning, Gene Therapy and Stem Cell
Research
Instructor:
Dr. Shahzad A. Mufti
Advisor Department of Biosciences
Cloning, Gene Therapy and Stem
Cell Research
Genomic equivalence of all body cells.
Spemann’s
experiments
of
delayed
nucleation.
Amphibian cloning to determine whether or
not nuclei undergo changes during
development,
Briggs
&
King(1950s)
experiments on Rana.
Nuclear isolation & transplantation into an
enucleated & activated egg.
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Cloning, Gene Therapy and
Stem Cell Research
Cloning of mammals: Wilmut’s “Dolly”
Nucleus from adult pregnant ewe mammary
glandinto
cultureat
Gl,
into
enucleated egg (at second meiotic
metaphase).
Fusion of donor cells with enucleated egg
through electric pulses, also egg activation.
Developing embryos then transferred into
uterus. One out of 434 eggs survived.
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Cloning, Gene Therapy and
Stem Cell Research
Mice, Cats, Cows also cloned.
Many develop diseases/abnormalities. “Also
not exactly identical” in all cases, due to
random chromosomal events.
Also faulty activation of genes, failure of
histone
modifications,
methylation
deficiencies. This cloning is NOT a good
reproductive technology.
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Embryonic Stem Cells and
Therapeutic Cloning
 Embryonic Stem Cells (ES Cells) pluripotent,
can be cultured for long period while remaining
undifferentiated.
 ES cells obtained through 2 major techniques;
from ICM of human embryos or from germ cells
of aborted fetuses.
 Importance of ES cells in medicine. Can produce
new population of cells to replace the deficient
ones in sick people; such as Alzheimer, or
Parkinson, or Spinal Cord Injury of Diabetics of
Anemic etc.
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Embryonic Stem Cells and
Therapeutic Cloning
 Quite successful in mice but not yet perfected
in humans; histocompatibility still a problem, so
rejection.
 Recent developments in “therapeutic cloning”
patient specific-------so no rejection. Adult
Stem Cells. Not successful yet. Difficult to
isolate and grow. Also not “very pluripotent”.
Partial success in Bone regeneration and
Neural regeneration.
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Basic types of stem cells
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Totipotent stem cells
Pluripotent stem cells
Multipotent stem cells
Unipotent stem cells
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Hello Dolly !!!!
Dolly the sheep – named after
singer Dolly Parton - was created
from a cell taken from a six-yearold donor sheep, using a
technique called somatic cell
nuclear transfer.
The birth of the Finn Dorset
sheep paved the way for other
animals to be cloned.
Cumulina
In 1997, scientists cloned the first
mouse from adult cells, calling her
Cumulina.
Cumulina died at the age of two
years and seven months – a
relatively healthy age for a mouse.
She gave birth to two litters during
her lifetime.
Mice remain one of the more
difficult species to clone.
Endangered species
In 2001, scientists announced
the birth of a cloned gaur, a rare
wild ox.
Noah, was created from the skin
cells of a male gaur that had
died eight years previously; but
Noah died just 48 hours after
delivery.
Cloning endangered species, or
even species that are extinct, has
been suggested as a method for
conserving animal populations.
GM cows
George and Charlie, born in
1998, were the first cloned
transgenic calves, paving the
way for "pharming".
With "pharming", scientists hope
to combine cloning and genetic
modification to create animals
capable of producing medicinal
products.
One of the calves' creators is
now president of a company
aiming to produce human
antibodies.
When cloning goes wrong….
Continued…..
Continued….