Cloning

HSC Biology | Free Study Notes

In this lesson

• what cloning is

• what gene cloning is

• what whole-organism cloning is

• the basic process of each

• common uses and limitations of cloning

What is cloning?

Cloning is the production of genetically identical copies of DNA, cells or organisms.

At this level, the two main types you need are:

• gene cloning

• whole-organism cloning

Gene cloning

Gene cloning is the production of many identical copies of a specific gene or DNA sequence.

What this means

Instead of copying a whole organism, gene cloning focuses on:

• one gene

• one DNA fragment

• one useful genetic sequence

Key idea

A 2020 HSC question identified gene cloning as the type of cloning being modelled when a human gene is being replicated in bacteria. 

Whole-organism cloning

Whole-organism cloning is the production of a genetically identical copy of an entire organism.

What this means

The offspring produced is genetically identical to the original source organism.

Key idea

A 2025 HSC question showed a sheep cloning process and identified the resulting offspring as clones of each other, because they developed from separated cells of the same early embryo. 

Gene cloning vs whole-organism cloning

Type of cloning	What is copied	Main outcome
Gene cloning	A gene or DNA sequence	Many copies of the same gene
Whole-organism cloning	An entire organism	Genetically identical individual(s)

Process of gene cloning

At this level, students should know the broad steps rather than every technical detail.

Basic process

1. A useful gene is identified and extracted.

2. A cloning vector and host organism are chosen.

3. Recombinant DNA is created.

4. The recombinant DNA is introduced into the host organism.

5. Organisms containing the recombinant DNA are selected.

A 2023 HSC multiple-choice question listed these as the five steps in gene cloning. 

Why bacteria are often used

Bacteria are commonly used because they:

• reproduce quickly

• can make many copies of the inserted gene

• are useful in recombinant DNA technology

Process of whole-organism cloning

There are different ways whole-organism clones can be produced, but at this level the main idea is that genetically identical cells are used to form new organisms.

Example from HSC material

A 2025 HSC question showed:

• an early embryo with identical cells

• the cells separated

• the cells multiplied

• embryos implanted into surrogates

• identical offspring developing as clones 

Key idea

If the starting cells are genetically identical, the resulting organisms are clones.

Uses of gene cloning

Gene cloning has important uses in biotechnology.

Medical use

Gene cloning can be used in recombinant DNA technology to produce useful substances.

A 2020 HSC marking guideline explains that bacteria can be given a human insulin gene so they produce insulin, which can then be used to treat diabetic patients. 

Agricultural use

Gene cloning is also linked to the development of transgenic organisms.

The syllabus specifically includes recombinant DNA technology and the development of transgenic organisms in agricultural and medical applications. 

Uses of whole-organism cloning

Whole-organism cloning can be used to preserve desirable traits.

Agricultural use

A 2020 HSC question identified the purpose of cloning in agriculture as preserving favourable traits in the offspring. 

Breeding use

Cloning may be used when there is a desire to reproduce an individual with particularly useful characteristics.

Limitations of cloning

Limitations of gene cloning

Gene cloning has limits because:

• it requires appropriate vectors and host organisms

• inserting a gene does not guarantee successful expression

• there may be ethical or social concerns depending on the application

At this level, the key point is that gene cloning is powerful, but it must be used carefully and effectively.

Limitations of whole-organism cloning

Whole-organism cloning has several important limits.

Reduced genetic diversity

A 2023 HSC marking guideline states that whole-organism cloning reduces biodiversity because cloned organisms are genetically identical to the parent organism. 

Limited commercial use

The same HSC guidance also notes that whole-organism cloning is not used commercially in cattle, so its current large-scale effect may be limited. 

Biological limitation

Because clones are genetically identical, cloning does not increase allele combinations in a population.

Why cloning matters in Module 6

Cloning is important in Module 6 because it shows how humans can deliberately manipulate genetic material and reproduction.

It links to:

• biotechnology

• recombinant DNA technology

• agriculture

• medicine

• effects on biodiversity

The syllabus specifically places cloning under genetic technologies and asks students to assess its effectiveness. 

Worked example

Exam-style question

Explain one difference between gene cloning and whole-organism cloning.

Worked answer

Gene cloning produces many identical copies of a specific gene or DNA sequence, while whole-organism cloning produces a genetically identical copy of an entire organism. Gene cloning focuses on one piece of genetic material, but whole-organism cloning reproduces the whole individual.

Why this works

This answer:

• compares both types directly

• explains what is copied in each

• keeps the distinction clear

Common mistakes

• Saying gene cloning and whole-organism cloning are the same.

• Assuming bacteria are used only in whole-organism cloning.

• Forgetting that gene cloning copies a gene, not a whole organism.

• Saying cloning increases genetic diversity.

• Describing the use of cloning without mentioning its limits.

Quick quiz

1. What is cloning?

2. What is gene cloning?

3. What is whole-organism cloning?

4. What is one use of gene cloning?

5. Why can whole-organism cloning reduce biodiversity?

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