7.6 - Cloning
Cloning in the natural world
● ***Cloning: genetically identical organisms produced from single parent organism (by
aseuxal reproduction\mitotic cell division)
● In plants/fungi, cloned offspring often remain physically attached to parent
Artificial cloning in plants and animals
● See leaf/stem cuttings
● ***In vitro (體外\繁殖): tissue culture\micropropagation - groups of cells of both
plants/animals isolated & grown (in artificial\laboratory conditions) producing whole
new organisms
● Micropropagation (plant tissue culture)
○ ***Explants (外植體): fragments of plants
○ Stages for tissue culture of explants:
1. Number of explants removed from selected parents plant
2. Surface of each explant sterilized with disinfectant solution, THEN
rinsed with sterile water (reducing chance of microbial
contamination during early stages of growth)
3. Sterilized explant placed inside sterile tissue culture vessel,
containing sterile growth medium
4. Growth medium contains nutrients, encouraging growth & division of
plant tissue cells to form mass of cells (callus [繭])
5. Callus transferred to fresh growth medium, containing mixture of plant
growth regulators, where it develops roots/stems/leaves →
becomes “plantlet”
1
Cloning in the natural world
● ***Cloning: genetically identical organisms produced from single parent organism (by
aseuxal reproduction\mitotic cell division)
● In plants/fungi, cloned offspring often remain physically attached to parent
Artificial cloning in plants and animals
● See leaf/stem cuttings
● ***In vitro (體外\繁殖): tissue culture\micropropagation - groups of cells of both
plants/animals isolated & grown (in artificial\laboratory conditions) producing whole
new organisms
● Micropropagation (plant tissue culture)
○ ***Explants (外植體): fragments of plants
○ Stages for tissue culture of explants:
1. Number of explants removed from selected parents plant
2. Surface of each explant sterilized with disinfectant solution, THEN
rinsed with sterile water (reducing chance of microbial
contamination during early stages of growth)
3. Sterilized explant placed inside sterile tissue culture vessel,
containing sterile growth medium
4. Growth medium contains nutrients, encouraging growth & division of
plant tissue cells to form mass of cells (callus [繭])
5. Callus transferred to fresh growth medium, containing mixture of plant
growth regulators, where it develops roots/stems/leaves →
becomes “plantlet”
1
