What is selective breeding?
-humans artificially select the plants or animals that are going to breed and have their genes remain the population, according to what e want from them
What are some best features wanting development in selective breeding?
- maximum yield of meat, milk, grain etc
- good health and disease resistance
- other qualities like temperament, speed, attractiveness, etc
What is the process of selective breeding?
- select the ones with best characteristics from your stock
- breed them with each other
- select the best of the offspring, and breed them together
- continue process over generations and the desirable traits will get stronger and stronnger
What are the drawbacks of selective breeding?
- the number of different alleles (gene pool)in a population is reduced
- this is due to farmers breeding the best, which are often related, this is known as inbreeding
- inbreeding can cause health problems
What are the risks of genetic engineering?
- inserted genes may have unexpected harmful side effects
- e.g. genes are often inserted into bacteria so they produce useful products, but if the bacteria mutated and became pathogenic, the foreign gene may make them more harmful and unpredictable
- some worry that engineered DNA can escape, e.g. weeds could gain rogue genes from a crop that has herbicide resistance inserted into it.
What is genetic engineering?
-moving genes from one organism to another so that it produces useful biological products
What are the advantages of genetic engineering?
-produces organisms with new and useful features very quickly
What are three examples of genetic engineering?
- gene for human insulin production has been put into bacteria. These are cultured and fermented, and the human insulin is extracted from he medium as they produce it
- cutting out the gene responsible in some plants for resistance to things such as herbicides, forest damage and disease, and inserting it into useful plants
- some parts of the world rely heavily on rice for food, and therefore vitamin A deficiency is a problem. The gene that controls beta-carotene production from carrot plants is taken and put into rice plants. Humans turn beta-carotene into vitamin A
What is the process of genetic engineering?
- the gene responsible for producing the desirable characteristic is selected
- it is then cut from the DNA using enzymes and isolated
- useful gene is inserted into DNA of another organism
- the organism then replicates and soon there are loads of similar organisms producing the same thing
What are the moral and ethical issues involved in genetic engineering?
- wrong to genetically engineer other organisms purely for human benefit, particularly if it is an animal, and the animal suffers
- later, those who can afford to may decide the characteristics of their children, and those who can’t may become the ‘genetic underclass’
What does gene therapy involve?
- altering a person’s genes in an attempt to cure genetic disorders
- it does not yet work properly
What are the two types of gene therapy?
- changing genes in body cells, particularly the most effected by the disorder. E.g. cystic fibrosis affects the lungs, so therapy for it would target the cells lining the lungs. Does not affect gametes, offspring can still inherit the disease
- changing genes in the gametes, so every cell of every offspring produced will be affected by gene therapy, and the offspring will not suffer the disease. Currently illegal
Why is gene therapy involving gametes controversial?
- unexpected consequences which cause new problems, these problems will then be inherited by all future generations
- may lead to ‘designer babies’, parents can choose the genes they want their children to have
