Selective BreedingSelective Breeding This is a form of artificial selectionThis is a form of artificial selection Involves choosing individuals from a Involves choosing individuals from a

population that have a certain trait population that have a certain trait and breeding those individualsand breeding those individuals

This is done across several This is done across several generationsgenerations

Eventually the trait is seen in all of the Eventually the trait is seen in all of the offspring and becomes more offspring and becomes more pronouncedpronounced

Used in farming, agriculture, and race Used in farming, agriculture, and race horseshorses

Reproductive Technology used in livestock

Artificial insemination (AI) – sperm from a selected animal is extracted and artificially introducing it into a female reproductive tract

Sex selection through sperm sorting – sperm are collected and analysed – separated into two groups – X and Y carrying sperm – uses a fluorescent dye

Reproductive Technology used in livestock

Multiple Ovulation Embryo Transfer (MOET) stimulate a female to produce

many eggs at once use AI to fertilise them within

the body after 6 days the uterus is flushed

to extract the embryos these are then inserted into

other females to begin gestation

CloningCloning

Cloning - creating genetically Cloning - creating genetically identical copies of an organismidentical copies of an organism

Two methods:Two methods: Splitting embryosSplitting embryos

Creating an embryo using IVF and using a Creating an embryo using IVF and using a fine needle to extract embryo cells that can fine needle to extract embryo cells that can divide and form new identical embryosdivide and form new identical embryos

Somatic Cell Nuclear Transfer (SCNT)Somatic Cell Nuclear Transfer (SCNT) Inserting the nucleus of a somatic cell into Inserting the nucleus of a somatic cell into

an ovum that has had its nucleus removedan ovum that has had its nucleus removed

Cloning

Gene TherapyGene Therapy

Gene Therapy

Still in development Attempts to introduce normal

copies of genes into the cells of an individual with a genetic disorder

Involves cloning the gene using a plasmid and then using a vector (carrier) to get it into the cells

Vectors include inactivated viruses and liposomes

Gene Therapy

Gene therapy for Haemophilia

Prenatal Gene Therapy

Stem CellsStem Cells

When sperm fertilises an ovum it forms a When sperm fertilises an ovum it forms a zygote. zygote.

The single cell grows and divides. Within The single cell grows and divides. Within 5 or 6 days there are up to 120 cells. 5 or 6 days there are up to 120 cells.

They form into a ball called the They form into a ball called the blastocyst. blastocyst.

Each cell is Each cell is pluripotentpluripotent, capable of , capable of developing into any cell type in the developing into any cell type in the human body such as heart, skin or hair.human body such as heart, skin or hair.

Blastocyst

Stem Cells

Can make every cell type in the

body.

They are ‘pluripoten

t’

A doctor takes a sample of skin cells from the patient and isolates their DNA. A donor egg cell, emptied of its own genetic contents, is injected with the DNA from the patient. The embryo is nurtured to grow and divide into a blastocyst. Some blastocyst cells are harvested and coaxed with growth factors to mature into insulin-producing cells. Millions of insulin-producing cells are injected back into the patient. The patient's diabetes is temporarily 'reversed', with no side effects.

Therapeutic Cloning – to produce stem cells

Genetic Genetic ScreeningScreening

Genetic screening Genetic screening can be performed for can be performed for a variety of reasons:a variety of reasons:

Test carrier status for Test carrier status for a particular disordera particular disorder

Test whether there is Test whether there is a predisposition to a predisposition to cancercancer

Pre-natal testing for Pre-natal testing for expectant parentsexpectant parents

Gel electrophoresis

DNA microarrays

Hybridisation

Pedigree analysis

Reproductive technologyReproductive technology Assist in overcoming infertilityAssist in overcoming infertility Variety of methods:Variety of methods:

In-vitro fertilisation (IVF)In-vitro fertilisation (IVF) – sperm and – sperm and ovum extracted and allowed to fuse ovum extracted and allowed to fuse outside of the body Embryo inserted outside of the body Embryo inserted into the uterus at the six cell stageinto the uterus at the six cell stage

Gamete Intra-fallopian Transfer Gamete Intra-fallopian Transfer (GIFT)(GIFT) – sperm and ovum extracted – sperm and ovum extracted and injected into the fallopian tube of and injected into the fallopian tube of the female so fertilisation happens in the female so fertilisation happens in the bodythe body

Reproductive technologyReproductive technology

Intracytoplasmic Sperm InjectionIntracytoplasmic Sperm Injection – – sperm and ovum extracted and the sperm and ovum extracted and the sperm is injected directly into the sperm is injected directly into the ovum. Embryo inserted into the ovum. Embryo inserted into the uterus at six cell stage.uterus at six cell stage.

Preventing pregnancy Preventing pregnancy (contraception) also falls under (contraception) also falls under the category of reproductive the category of reproductive technologytechnology

IVF

GIFT

Intracytoplasmic Sperm Injection

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Biochallenge Page 652

Chapter Review: 2, 3, 4, 5, 6, 7, 9bcd, 11, 12