IGCSE BIOLOGY SECTION 5 LESSON 3

Content Section 5 Uses of biological resources a)Food production b)Selective breeding c)Genetic modification (genetic engineering) d)Cloning

Content Lesson 3 d) Cloning 5.17 describe the process of micropropagation (tissue culture) in which small pieces of plants (explants) are grown in vitro using nutrient media 5.18 understand how micropropagation can be used to produce commercial quantities of identical plants (clones) with desirable characteristics 5.19 describe the stages in the production of cloned mammals involving the introduction of a diploid nucleus from a mature cell into an enucleated egg cell, illustrated by Dolly the sheep 5.20 evaluate the potential for using cloned transgenic animals, for example to produce commercial quantities of human antibodies or organs for transplantation.

What is cloning?

Cloning is the production of genetically identical individuals

Examples of Clones

Strawberry runner

Strawberry runners (stolons) are horizontal stems that run along the ground and produce new clone plants at ‘nodes’ spaced at varying intervals. Clone plant Internode

Cuttings Geranium

Cuttings Geranium Plant with desired characteristics

Cuttings Geranium Plant with desired characteristics Produce many copies by taking stem, leaf or root cuttings

Cuttings Geranium Plant with desired characteristics Produce many copies by taking stem, leaf or root cuttings Grow in damp atmosphere until roots develop

Tissue culture Parent plant with desired characteristics

Tissue culture Parent plant with desired characteristics Cells taken from shoot tip with sterile forces = EXPLANT

Tissue culture Parent plant with desired characteristics Cells taken from shoot tip with sterile forces = EXPLANT Cells grown on nutrient agar  CALLUS culture

Tissue culture Parent plant with desired characteristics Cells taken from shoot tip with sterile forces = EXPLANT Cells grown on nutrient agar  CALLUS culture Shoot stimulating hormone added

Tissue culture Parent plant with desired characteristics Cells taken from shoot tip with sterile forces = EXPLANT Cells grown on nutrient agar  CALLUS culture Shoot stimulating hormone added Root stimulating hormone added

Tissue culture Parent plant with desired characteristics Cells taken from shoot tip with sterile forces = EXPLANT Cells grown on nutrient agar  CALLUS culture Shoot stimulating hormone added Root stimulating hormone added Many genetically identical plantlets

Tissue culture Parent plant with desired characteristics Cells taken from shoot tip with sterile forces = EXPLANT Cells grown on nutrient agar  CALLUS culture Shoot stimulating hormone added Root stimulating hormone added Many genetically identical plantlets Micropropagation = rapidly multiplying required stock plants to produce a large number of identical plants

Tissue culture Parent plant with desired characteristics Cells taken from shoot tip with sterile forces = EXPLANT Cells grown on nutrient agar  CALLUS culture Shoot stimulating hormone added Root stimulating hormone added Many genetically identical plantlets Micropropagation = rapidly multiplying required stock plants to produce a large number of identical plants Process must be aseptic (carried out in the absence of harmful bacteria) or else the new plants will rot.

Cloning animals Dolly the sheep

Cloning animals Dolly the sheep Camel Carp Cat Cattle Dog Ferret Frog Fruit flies

Cloning animals Dolly the sheep Camel Carp Cat Cattle Dog Ferret Frog Fruit flies Goat Horse Mice Mouflon Mule Pig Rabbit Wolf

Cloning animals - The technique Ewe ‘A’Ewe ‘B’

Cloning animals - The technique Ewe ‘A’Ewe ‘B’ Remove mammary cells from udder

Cloning animals - The technique Ewe ‘A’Ewe ‘B’ Remove mammary cells from udder Mammary cell with nucleus

Cloning animals - The technique Ewe ‘A’Ewe ‘B’ Remove mammary cells from udder Mammary cell with nucleus Ovum (egg)

Cloning animals - The technique Ewe ‘A’Ewe ‘B’ Remove mammary cells from udder Mammary cell with nucleus Ovum (egg) Remove nucleus Enucleate ovum

Cloning animals - The technique Ewe ‘A’Ewe ‘B’ Remove mammary cells from udder Mammary cell with nucleus Ovum (egg) Remove nucleus Enucleate ovum Electrofusion

Cloning animals - The technique Ewe ‘A’Ewe ‘B’ Remove mammary cells from udder Mammary cell with nucleus Ovum (egg) Remove nucleus Enucleate ovum Electrofusion Fusion

Cloning animals - The technique Ewe ‘A’Ewe ‘B’ Remove mammary cells from udder Mammary cell with nucleus Ovum (egg) Remove nucleus Enucleate ovum Electrofusion Fusion Developing embryo implanted into surrogate mother, Ewe ‘C’

Cloning animals - The technique Ewe ‘A’Ewe ‘B’ Remove mammary cells from udder Mammary cell with nucleus Ovum (egg) Remove nucleus Enucleate ovum Electrofusion Fusion Developing embryo implanted into surrogate mother, Ewe ‘C’ Cloned lamb born, genetically identical to Ewe ‘A’

Cloning animals - The technique The first animal cloned by this method was the sheep, named Dolly in honour of the Country & Western singer Dolly Parton, in 1996

Cloning animals - The technique The first animal cloned by this method was the sheep, named Dolly in honour of the Country & Western singer Dolly Parton, in 1996 Dolly was the first success in 277 attempts. Dolly was put down at the age of 6 in 2003, suffering from a form of lung cancer caused by a virus.

Transgenic animals

An organism treated by genetic modification is called a transgenic organism.

Transgenic animals An organism treated by genetic modification is called a transgenic organism. The majority of transgenic animals produced so far are mice.

Transgenic animals An organism treated by genetic modification is called a transgenic organism. Animals can produce substances that are not part of their normal metabolism. The majority of transgenic animals produced so far are mice.

Transgenic animals An organism treated by genetic modification is called a transgenic organism. Animals can produce substances that are not part of their normal metabolism. The majority of transgenic animals produced so far are mice. For example, an anti-blood clotting agent used in heart surgery has been produced in the milk of transgenic goats.

Transgenic animals An organism treated by genetic modification is called a transgenic organism. Animals can produce substances that are not part of their normal metabolism. The majority of transgenic animals produced so far are mice. For example, an anti-blood clotting agent used in heart surgery has been produced in the milk of transgenic goats. There are at least five different transgenic species, developed to produce specific proteins in their milk, including an anti-cancer antibody.

Transgenic animals An organism treated by genetic modification is called a transgenic organism. Animals can produce substances that are not part of their normal metabolism. The majority of transgenic animals produced so far are mice. For example, an anti-blood clotting agent used in heart surgery has been produced in the milk of transgenic goats. There are at least five different transgenic species, developed to produce specific proteins in their milk, including an anti-cancer antibody. Xenotransplantation – the transplantation of living cells, tissues or organs from one species to another.

The development of transgenic animals, and the possibility of xenotransplantation, raise serious moral and ethical questions.

You need to read about these emotive subjects very carefully, and develop your own views based upon the information available.

The development of transgenic animals, and the possibility of xenotransplantation, raise serious moral and ethical questions. You need to read about these emotive subjects very carefully, and develop your own views based upon the information available. In the exam you may well be asked to: “evaluate the potential for using cloned transgenic animals, for example to produce commercial quantities of human antibodies or organs for transplantation.”

End of Section 5 Lesson 3 In this lesson we have covered: cloning tissue culture cloning animals transgenic animals