Cloning

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Dolly the sheep

-Obtain an udder cell from one parent sheep (donor).

-Another parent sheep is the egg cell donor sheep, the nucleus of the ovum is removed (the ovum is now enucleated) and replaced with the udder cell.

-The cell now formed has the exact same genetic information as all the cells in the donor of udder cell.

-The cell develops into an embryo.

-Embryo transferred into foster mother (cells would divide by mitosis and eventually specialise)

-The lam born is genetically identical to the parent sheep (donor of udder cells).

*It's easier to transfer the udder cell rather than just a nucleus, because a nucleus alone could too easily be damaged.

*Attempts made to clone other animals but failed - genes transferred to the egg are old genes - much more research needed to make technique reliable.

Cloning plants

Micropropagation

-Remove tips of stems, side shoots (explants)

-Trim explants to size about 0.5-1mm, placed in agar medium that contains nutrients and plants hormones.

-More explants can be taken as long as there is supply

-explants with shoots transferred to another culture medium containing a different balance of plant hormones to induce root formation

-When roots are grown: explants transferred to greenhouses and transplanted into compost. gradually acclimatised to normal growing conditions

-Atmosphere in greenhouses moist - reduce water loss.

Advantages

Large numbers of genetically identical plants can be produced rapidly.

Large number of plants can be stored easily

Produce plants that are hard to grown from seeds and cuttings

Produce plants any time of the year

Can be introduced to thousands of plants quickly