VL1 Klonierung Flashcards
Definition: Klone
Genetische identische Organismen oder Molekuele, die auf einem gemeinsamen Vorfahren breuhen.
Varianten von Klonierung
Artifizielle Klonierung / Natuerliche Klonierung
Varianten von artifizielle Klonierung
- Reproduktives Klonieren – Das gesamte Tier wird ausgehend von einer Zelle durch asexuelle Reproduktion erstellt
- Therapeutisches Klonieren – Kein identisches Individuum, sondern Erstellung von Gewebe.
- Genklonierung - Gene oder Genfragmente werden kloniert
Varianten von natuerliche Klonierung
- Klonieren von einzelligen Organismen durch Isolierung
- Pflanzliche asexuelle Replikation (Apomixis)
- Zwillinge
Klonierung aus Einzelzellen in Pflanzen: Beispiel / Schritten?
(= tissue culture, micropropagation)
example: carrots
- Plug of tissue is removed, dissociated into single cells (eg from carrot root)
- single cells are transferred to growth medium
- cells divide to form callus
- each callus is transferred to new medium to induce root and shoot formation
- plants are transferred to soil and grown into carrots
result: genetically identical
Klonierung aus Einzelzellen in Pflanzen: Ergebnis?
Genetically identical, or cloned carrots, derived from a single ancestor
Klonierung von Tieren: Ansaetze?
erstes erfolgreiche Experimente an Saugern in den 80ern
zwei Ansaetze:
- embryo splitting
- Kerntransfer
Klonierung von Tieren: Embryo Splitting
Schritte?
- Embryo is split to form two half-embryos
- Embryos are transferred to an unrelated surrogate mother
- Pregnancy is monitored by ultrasound
- sheep gives birth to identical twins
Klonierung von Tieren: Kerntransfer
–
Dolly
–
schritte usw
Dolly - Klonierungseffizienz
– Zellen wurden von einem 6 Jahre alten Finnish Dorset Schaf entnommen und im Labor kultiviert
– 277 dieser Zellen wurden mit 277 Eizellen (ohne Nukleus) fusioniert
– 29 Eizellen überlebten und wurden in Blackface Leihmütter implantiert
– 1 Geburt = Dolly
– Erfolgsrate:
• 0.3% bei Beginn
• 3.4% nach Implantierung
• Nach Befruchtung in utero: 33-50% entwickeln sich
Andere klonierte tiere
goats, cats, cows, dogs
Probleme bei Klonen durch Kerntransfer
- Geringe Lebenserwartung / Krankheiten
- Unterschiede wegen somatischer Mutationen
- Niedrige Erfolgsrate: 0.1 - 3%
- Dedifferenzierung nicht komplett (bei somatischer Zellen (differenziert) Chromatin anders - tabula rasa rueckgaengig zu machen - funktioniert nicht vollstaendig)
- Telomere können verkürzt sein
- Mitochondrien können defekt sein
English three-parent babies:
How?
Purpose?
Produced from genetic material of one man and two women through use of assisted reproductive technologies: mitochondrial manipulation (or replacement) technologies and three-person in vitro fertilization (IVF).
Reproductive technologies used focus on replacing / reducing effects of mutations that occur in mitochondrial DNA.
The various approaches could help women to overcome infertility and could prevent transmission to offspring of potentially debilitating mitochondrial diseases.
Klonierung von Genen
Ziel: Vereinzeln, um zu manipulieren und zu verfielfältigen.
Gen –> Klonierungsvektor –> Wirt –> Vervielfaeltigung
Restriktionsenzyme:
Beispiel?
Funktionsweise?
EcoRI
- binds to the recognition sequence and cuts the DNA into fragments
- EcoRI has sticky ends (as opposed to blunt end)
Restriktionsenzyme?
(=restriction endonuclease, restrictase)
cleaves DNA into fragments at or near specific recognition sites within molecules known as restriction sites.
One class of broader endonuclease group of enzymes.
Restriktionsenzyme:
Classification and types?
Commonly classified into 5 types: differ in structure and whether they cut their DNA substrate at recognition site, or if recognition and cleavage sites are separate.
More than 3,600 restriction endonucleases known,
Restriktionsenzyme:
Origin? Purpose?
Restriction modification System?
Found in bacteria and archaea.
Provide defense mechanism against invading viruses.
Inside prokaryote, restriction enzymes selectively cut up foreign DNA (=restriction digestion), meanwhile, host DNA is protected by modification enzyme (a methyltransferase) that modifies the prokaryotic DNA and blocks cleavage.
Together, these two processes form the restriction modification system.
Restriktionsenzyme:
Use?
More than 800 available commercially.
Routinely used for DNA modification in laboratories
a vital tool in molecular cloning
Shotgun Klonieriung?
method in cloning genomic DNA .
involves taking DNA to be cloned, cutting it either using a restriction enzyme or randomly using a physical method to smash the DNA into small pieces. These fragments are then taken together and cloned into a vector. The original DNA can be either genomic DNA (whole genome shotgun cloning) or a clone such as a YAC (yeast artificial chromosome ) that contains a large piece of genomic DNA needing to be split into fragments.
Shotgun Klonierung:
Schritte?
- a selected restriction enzyme cuts a specific base sequence everywhere it occurs in a chromosome or in cDNA
- the same enzyme cuts the same sequence in plasmid DNA
- the chromosomal DNA or cDNA fragments have sticky ends
- the plasmid DNA also has sticky ends
- the plasmid DNA and the foreign DNA are mixed in a solution with other enzymes that can seal them together
- the result: a collection of recombinant plasmids that incorporate foreign DNA fragments.
- host cells that can divide rapidly take up the recombinant plasmids
Shotgun Klonierung:
research more
Shotgun Klonierung:
research more
Vektoren?
Plasmide, um DNA Fragmente zu klonieren