Klonierung von Säugetieren und Gentechnologie

Klonierung von Säugetieren und
Gentechnologie
Dolly
Dolly with her first
newborn, Bonnie
• Born in July 1996 at the Roslin
Institute in Scotland
• First mammal to be cloned
from an adult mammal using the
nuclear transfer technique
• 277 attempts were made
before the experiment was
successful
•Dolly died in February 14, 2003
of progressive lung disease at
the age of 6; whereas normal
sheep can live up to 12 years of
age.
Mammal Cloning
http://www.howst
uffworks.com/cloni
ng.htm/printable
January 8, 2001 Noah, a baby bull gaur, became the first
clone of an endangered animal.
Tetra
1998 – 50 mice were cloned in three
generations from a single mouse
1998 – 8 calves were cloned from a single
adult cow, but only 4 survived to their first
birthday
1999 – A female rhesus monkey named Tetra
was cloned by splitting early embryo cells.
2000 – Pigs and goats reported cloned from
adult cells
2002 – Rabbits and a kitten reported cloned
from adult cells
http://hs.houstonisd.org/
hspva/academic/Science/
Thinkquest/gail/text/bene
fits.html
• Genetic Savings and Clone has
successfully cloned cats, including CC
(above), the first cloned cat. The
• company had four clients sign up to
• have their domestic cats cloned for
U.S. $50,000 each.
Klonierung von Haustieren
Genetic Savings &
Clone promises to
clone anyone’s pet —
for $50,000
First pet clone is a cat
Vergleich der Erfolgsrate bei
verschiedenen Tieren
Species
Number of
oocytes used
Number of
live offspring
Notes
Mouse
2468
31 (1.3%)
-
Bovine
440
6 (1.4%)
2 died
Sheep
417
14 (3.4%)
11 died
within 6
months
Pig
977
5 (0.5%)
-
Goat
285
3 (1.1%)
-
The table shows success rates of cloning when mature mammal cells were
used.
Yanagimachi, R. 2002. "Cloning: experience from the mouse and other animals." Molecular and Cellular Endocrinology. 21 March,
187.
Kern - Transplantation
Enucleation of donor cell
Nuclear Transfer
• the nucleus of the individual to be cloned is
transferred to the cytoplast in one of the 2 ways:
1) electrofusion – whole nucleus donor cell
injected beneath the zona pellucida (the outer
membrane of the oocyte) and fusion of cells
induced by electrical impulses
2) nuclear injection – naked nucleus microinjected
into cytoplast
Zusammenfassung
oocyte
cytoplast
ENUCLEATION
NUCLEAR
TRANSFER
cytoplast
clone cell
genetic
reprogramming
Induktion der
EmbryoEntwicklung
developing embryo in culture
Implantation
embryo
uterus of
surrogate mother
Genetische Reprogrammierung
Fig. 5 from Nature Reviews Genetics 3: 671
Cloning Humans
http://www.cnn.com/2001/WORLD/europe/08/06/clone.doctor/index.html
Klonierung von Menschen?
therapeutisch oder reproduktiv?
http://www.humancloning.org/
Human Cell Embryos
Clonaid
http://www.clonaid.com/
“The main goal of CLONAID™ is to offer reproductive
human cloning on a worldwide basis to infertile
couples, homosexual couples, people infected with the
HIV virus as well as to families who lost a beloved
family member.”
http://www.clonaid.com/
• Clonaid was founded by
members of a religious sect
called the Raelians
• On Thursday, December 26, 2002, Clonaid claimed to have
successfully created the first human clone, a 7 pound baby
girl named Eve
• Eve was created using DNA from her mother’s skin cells
and is a genetic twin of her mother, a 31-year-old American
citizen
• After originally stating that a panel of independent scientists
would be allowed to verify that Eve was a clone of her mother,
on January 3, 2003 it was announced that no tests would be
performed to prove Eve’s existence or that she was a clone
• Clonaid now claims that 5 cloned humans have been born, the
most recent being born February 4, 2003
• There is still no proof that a human clone has ever been born
• Many scientists believe that the Clonaid claim is a hoax
Klonierung beim Menschen:
Sixth Cloned Baby Born DownUnder !
The 6th cloned baby was born on
Thursday the 5th of February in
Australia.The Clonaid team, after
20 more implantations, had 8
successful pregnancies.
Probleme mit Klonierung
• Klonieren ist nicht sicher
• beim Klonieren entstehen
Entwicklungsdefekte
•Klone scheinen vorzeitig zu altern
Clones are Not Exact Copies
• A clone’s mitochondrial DNA comes from the donor egg
cell. Unless the donor egg comes from the person being
cloned their mitochondrial DNA will be different.
• Random developmental events, such as X-chromosome
inactivation, can cause clones to differ greatly in
appearance.
• Different environmental and social factors can cause
clones to vary greatly in both appearance and personality.
• No clone will ever be exactly the same as the original.
• Rainbow and Cc (cloned cat)
• Cloned cat hardly resembles her
original
http://www.crystalinks.com/cloningcats.html
Geburtsdefekte bei Klonen
• Klone leiden unter dem “large offspring syndrome”, beim
dem sowohl das Neugeborene als auch die dazu gehörige
Plazenta ungewöhnlich groß sind
• Klone haben oft unerklärliche Atmungs- oder
Kreislauferkrankungen
• Das Immunsystem ist häufig geschwächt oder
funktionsunfähig
• Sehr wenige Klone erreichen das adulte Alter
Sicherheit bei der Klonierung
•Die Erfolgsrate bei der Klonierung ist teilweise extrem niedrig
•Beim Klonieren entstehen häufig Entwicklungsdefekte
•Dadurch haben Klone oft Geburtsfehler
• Dolly (left) and her surrogate mother
• It took 277 attempts before Dolly
became the first cloned sheep
Vorzeitige Alterung bei Klonen
• Klone scheinen schneller zu alter als normale Individuen
• Dolly zeigte in relativ jungen Jahren heftige Arthritis
• Bei Dolly hatten die Telomere (spezielle Strukturen an
den Chromosomenenden) eine zu geringe Größe
•Neuere Untersuchungen zeigen aber, dass die Telomerase in
Embryonalstadium aktiv wird und die Telomerlängen größer
werden
http://users.rcn.com/jkimball.ma.ultranet/BiologyPag
es/T/Telomeres.html
http://www.zks.uni-freiburg.de/dereg_new/diagramme.html
http://www.zks.uni-freiburg.de/dereg_new/diagramme.html
http://www.zks.uni-freiburg.de/dereg_new/diagramme.html
Erfolgreiche Gentherapie mit
tödlichen Nebenwirkungen
• X-linked severe combined immunodeficiency
disease (X-SCID), bekannt als "bubble baby
syndrome.„
• 11 Patienten fehlte das Gen IL2RG
• Das Gen wurde in Stammzellen der Kinder
überführt
• Zwei (inzwischen 3) Kinder entwickelten
Leukämie, bzw eine lymphatischen Tumor
• Das Transgen war bei beiden Kindern in das
Tumorgen LMO2 hinein gesprungen
Pflanzengentechnologie
Ein natürlicher Helfer für die
Pflanzengentechnologie ist das Bakterium
Agrobakterium tumefaciens
Tumorgallen durch A. tumefaciens
Pflanzengentechnologie
A.
tumefaciens injiziert die T-DNA in die Pflanzenzelle,
um sie zu mehr Wachstum anzuregen
Pflanzengentechnologie
DNA-Transfer mit Hilfe von Agrobakterium tumefaciens
http://www.sciencemag.org/cgi/reprint/294/5550/2317.pdf
Typischer Pflanzenvektor auf der Basis des
Agrobakterium tumefaciens Ti-Plasmids
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