Demonstrate understanding of human manipulations of genetic transfer and its biological implications
What this domain tests
This domain assesses human manipulations of genetic transfer and their biological implications. You need to explain techniques such as selective breeding, cloning, transgenesis and gene editing, and evaluate biological, ethical, legal and economic consequences.
Core rules and concepts
- Selective breeding changes allele frequencies by choosing individuals with desired traits; it reduces genetic diversity.
- Cloning produces genetically identical individuals. Reproductive cloning uses somatic cell nuclear transfer; it can cause developmental abnormalities.
- Transgenesis transfers a gene from one species to another, e.g., Bt maize carries a bacterial gene for insect resistance.
- Gene editing, such as CRISPR-Cas9, makes targeted changes to DNA. It can be used in crops, animals and gene therapy.
- Biological implications include gene flow to wild relatives, effects on non-target species, increased antibiotic resistance, and loss of biodiversity.
- Ethical and legal issues include informed consent, animal welfare, patenting, and cultural values.
Worked example
Bt maize is engineered with a gene from Bacillus thuringiensis that produces a protein toxic to certain insect larvae. Biological benefit: reduced chemical insecticide use. Biological risk: selection for resistant insects and possible effects on non-target species. Economic benefit: higher yield. Ethical concern: gene flow to nearby non-GM maize. A reasoned evaluation weighs these factors rather than declaring the technology simply good or bad.
Traps that cost marks
Confusing cloning with transgenesis; ignoring ecological risks; claiming all GMOs are identical; failing to distinguish biological from ethical or economic implications.