How do humans deliberately change the genetics of organisms, and what are the implications?
Describe selective breeding, transgenic organisms and cloning, and evaluate their applications and implications
A focused answer to the WACE Year 12 Biology dot point on reproductive and cloning technologies. Covers selective breeding, transgenic organisms, reproductive and therapeutic cloning, and the ethical and biological implications with Australian examples.
Reviewed by: AI editorial process; not yet individually human-reviewed
Have a quick question? Jump to the Q&A page
What this dot point is asking
SCSA wants you to describe each technology, give a real application, and evaluate the benefits against the biological and ethical implications. A strong answer balances clear description with a reasoned discussion of consequences.
Selective breeding
Selective breeding (artificial selection) is the oldest form of genetic manipulation. Humans choose individuals with desirable traits and breed them together, so that over many generations those traits become more common. It has produced high-yield wheat, dairy cattle that give more milk, and merino sheep bred in Australia for fine wool.
A drawback is reduced genetic diversity: by repeatedly breeding from a narrow group, the gene pool shrinks, which can increase the frequency of harmful recessive conditions and leave a breed less able to resist new diseases.
Transgenic organisms
A transgenic (genetically modified) organism contains a gene transferred from another species, made using the gene technology techniques of restriction enzymes, ligase and vectors. Examples include bacteria engineered to produce human insulin, and crops modified for pest resistance or improved nutrition.
Benefits include cheaper medicines and higher crop yields. Concerns include the possible spread of inserted genes to wild relatives, effects on non-target organisms, and questions about long-term safety and corporate control of seed.
Cloning
Cloning produces genetically identical organisms or cells.
- Reproductive cloning creates a whole organism genetically identical to another, as with Dolly the sheep, produced by somatic cell nuclear transfer.
- Therapeutic cloning produces stem cells genetically matched to a patient for medical treatment, rather than a whole organism.
Reproductive cloning raises welfare concerns (low success rates, health problems in clones) and ethical questions, while therapeutic cloning raises debate about the use of embryos.
Evaluating applications and implications
A good evaluation considers several dimensions: the biological consequences (such as reduced genetic diversity or gene escape), the ethical issues (animal welfare, consent, fairness of access), the economic effects (cost, who benefits), and the regulation in place. In Australia, gene technology is regulated by the Office of the Gene Technology Regulator, which assesses risks before approving the release of genetically modified organisms.
Why this matters for continuity
These technologies show that humans can now direct the genetics of other species deliberately, accelerating change that natural processes would take many generations to produce, or producing combinations that could never arise naturally. Understanding the biology lets you assess the claims made for and against them, which is increasingly important as the technology reaches agriculture, medicine and conservation in Australia.