Genetic engineering changes an organism's genome
Definition
Genetic engineering
Changing an organism's characteristics by transferring a gene from one organism into another, so the second organism produces a desired protein or feature.
- Genetic engineering is the deliberate modification of an organism's genome by inserting, removing or changing DNA to produce a desired inherited characteristic.
- A gene contains the base sequence for a protein, so transferring a gene can give the recipient cell instructions to make a new protein.
- The inserted gene becomes part of the recipient's genetic material and can be copied when the cell divides.
- An organism containing DNA introduced from another species is described as transgenic.
- Genetic engineering targets a known gene, while selective breeding mixes many alleles from two parents.
Example
A human insulin gene can be placed in bacteria, which then make human insulin protein when the gene is expressed.
Desired features depend on gene expression
- The transferred gene must enter suitable cells and be switched on for its protein to be made.
- A regulatory DNA sequence may be needed so the host cell transcribes the inserted gene.
- Successfully modified cells must be identified and copied to produce enough cells or a complete organism.
- The new phenotype depends on the protein's action, such as producing an insecticidal protein or a medically useful hormone.
Common Mistake
Do not write that a gene is an organism's characteristic; the gene codes for a product that helps produce the characteristic.
Exam technique
Link gene transfer to protein production, then link the protein to the desired phenotype.
Self review
- What is genetic engineering?
- How can an inserted gene change a phenotype?
- What does transgenic mean?
- How does genetic engineering differ from selective breeding?
