Cloning

Plants

Clones are genetically identical organisms that have the exact same DNA as the parent. Cuttings are traditional cloning technique used to grow plants.

1. Cutting is taken from a stem, leaf, or root

2. Cutting is dipped in rooting powder and then placed in well watered compost

3. Bag is placed around the plant and pot to provide humid conditions and decrease transpiration while the cutting is developing roots

A modern version of taking cuttings is tissue culture (micropropagation). This is carried out in a lab and often described as in vitro (in glass)

1. Tips of stems, roots, or shoots (explants) are taken from the plant and trimmed to 0.5-1mm.

2. Explants are washed in mild bleach to kill any microorganisms and placed in an agar plate with nutrients and plant hormones for cell division and growth to form a callus

3. Once the explants have grown shoots and roots (plantlets), they’re transferred to green houses and transplanted into compost, and are slowly acclimatised to normal growing conditions

advantages

• large numbers of genetically plants can be produced rapidly

• Species that are hard to grow from seeds can be propagated easier

• Able to grow seasonal foods all year round

• large number of plants can be stored easily (cold storage)

• Genetic modifications can be introduced to lots of plants quickly

uses

• can produce virus free plants, even from cuttings they can get infected

Animal

why?

• animals with desirable characteristics can be produced quickly and reliably

• helps build up populations of rare animals that are near extinction

process (dolly the sheep 🐑)

1. haploid nucleus of an unfertilised egg is removed to form an enucleated egg cell (egg cell without a nucleus)

2. diploid nucleus from donor is placed into the enucleated egg cell and fused with an electric pulse

3. another electric pulse triggers mitosis to form an embryo

4. the developing embryo is implanted into the uterus of a surrogate, which gives birth once it’s fully grown

disadvantages

• low success rate - Dolly was made after 237 attempts

• embryos live shorter lives - because the cells are from animals who have already lived a few years

• increased birth size → birth difficulties, breathing and circulation problems

• defects in organs

reproductive cloning - producing a new organism

therapeutic cloning - producing an embryo and in its early stages cells are removed to produce new organs