Clones

Genes, cells or whole organisms that have identical genetic materials, DNA.

Natural Clones:

• Bacteria carry out binary fission to divide (Prokaryotes)
• Identical twins - where the zygote splits in two
• Strawberry Runners/Stolons - the new plants are clones
• Tubers - swollen stems/roots like potatoes or radishes
• Bulbs - fleshy leaves such as onions
• Basal Sprous - root suckers like rasperries/loganberries

structures produced asexually (mitosis) that can grow into new individuals - cloned organisms

It occurs after damage to the main plant (Elm Trees) where basal sprouts can gow two months after the tree dies ->these suckers grow from meristem tissue

1)Healthy Elm with Root Suckers

2) Elm starting to show symptoms of Dutch elm disease caused by a fungus carried in a beetle vector

3) Main stem dies but the roots are alive and producing root suckers

4) Root suckers grow but the largest one shows symptoms of the disease (genetically identical so is as susceptible as parent plant)

• Cuttings - cut near a leaf node -> prodcues many plants
• Grafting - a woody shoot is put in a stem with roots (root stock)

Tissue Cultures:

• Stem cells are taken from stem/root/shoot tip of a parent plant - these cells are called an explant
• Cells sterilised to kill bacteria/fungi which would compete for nutrients with the plant cells
• Cells placed on a culture medium (glucose, auxins and cytokinins). The cells divide by mitosis but do not differentiate - a callus
• When the cells have gone through mitosis, into a small plant, they are planted into a genetically identical plant

Why?

• To clone plants that don't readly reproduce or are rare
• Grow whole plants tha are from genetically engineered plant cells
• to produce many clone very quicky-  when cells are subcultured, this is called micropropagation

Advantages

• High-value animals cloned in large numbers
• Preservation of rare species
• Genetically modified animals are quickly reproduced

Disadvantages

• Animal welfare concerns
• Genetic uniformity makes species unable to adapt to their environment
• Expensive
• Unclear how clones will behave

Finn Dorset mammary cell  Scottish Blackface Ovum

Nucleus from Mammary cells  Remove Nucleus from Ovum

Electofusion - Reconstructed cell of Blackface cytoplasm and Finn Dorset Nucleus

'culture' is tied in oviduct of sheep

Implant embryo into surrogate's uterus

Cloned Finn Dorset ewe is born -> Dolly

Collect eggs from a high value female Collect Sperm from a high value male

In vitro Fertilisation

Grow in vitro to a 16 cell embryo

Split embryo into several separate segments

Implate into surrogate mothers

Each calf is a clone

Artificial identical twins - Developed in 1979 and in 2000, the first rhesus monkey 'Tetra' was cloned

used cloned cells to generate cells, tissues and organs to replace ones damaged by disease/accident. The techniques are often referred to as therapuetic cloning.

People object to its use in humans due to its use of embryonic material and scienftific concern about a lack of understanding of how cloned cells behave over time

Advantages

• Being genetically identicl to body cells means the immune system will not recognise them as foreigh and reject them
• End the problem of waiting for donor organs to be avaliable for transplant
• Cloned cells are totipotent
• cloned cells are less dangerous than major, invasive surgery

Possible uses

• Regeneration of heart muscle after a heart attack
• Repair of nervous tissue destroyed by disease (Multiple Sclerosis)
• Repairing the spinal cord of paralysed with broken backs/necks