B3 - New genes for old

• The are possible problems with selective breeding programmes. They may lead to inbreeding, where two closely related individuals mate, and this can cause health problems within the species. 
• Inbreeding can cause a population of alleles in the population (the gene pool). This can lead to:

- an increased risks of harmful recessive characteristics showing up on the offspring.

- a reduction in variation, so that populations cannot adapt or change so easily.

• Genetic engineering has advantages and risks:

- One advantage - organisms with desired features can be produced very quickly.

- One disadvantage - negative, harmful side effects.

• To carry out genetic engineering, four steps are taken:

- The desired characteristics are selected

- The genes responsible are identified and removed (isolation)

- The genes are inserted into other organisms.

- The organisms are allowed to reproduce (replication).

• The process of using genetic engineering to cure certain diseases and/or change a persons genes is called gene therapy.
• Gene therapy could involve body cells or gametes. Changing the genes in gametes are much more controversial. Because it is difficult sometimes to decide which gene parent should be allowed to change. It could lead to 'designer babies'.