Natural and Artificial Clones Unit 2 Module 2 – Biotechnology and Gene Technologies

Learning Objectives Understand what clones are. Understand the advantages and disadvantages of asexual reproduction. Understand what natural vegetative propagation in plants is. Understand what artificial propagation is. Understand the use of tissue culturing.

Clones Clone: Genes, cells or whole organisms that carry identical genetic material because they are derived from the same original DNA. Examples: Identical twins (when zygote splits). Plants producing runners. Binary Fission in bacteria. Cloning is a natural process for growth/reproduction, but can also be artificial.

Asexual Reproduction The basis of asexual reproduction in eukaryotes is mitosis. In single-celled eukaryotes, cells split to produce two cloned offspring. In multi-cellular organisms (namely plants), some of the cells produced by mitosis can grow into new, separate organisms with identical DNA to the parent plant.

Advantages of Asexual Reproduction Quick – allows organisms to reproduce rapidly and take advantages of resources. Can be completed if sexual reproduction fails or is not possible. All offspring have the genetic information to enable them to survive in their environment.

Disadvantages of Asexual Reproduction Asexual reproduction does not produce any genetic variety. This means any genetic parental weakness will be in all offspring. If the environment changes, all genetically identical organisms will be equally susceptible.

Natural Vegetative Propagation An example of a plant that reproduces asexually is the English elm (Ulmus procera). If the main trunk is destroyed (disease/burning), growths called root suckers (basal sprouts) appear within 2 months. The suckers grow from the meristem tissue in the trunk close to the ground. This is where the least damage is likely to have occurred. See figure 2 on page 153 of the textbook.

Task Answer Questions 1-4 on page 153 of the textbook. Answers on page 262.

Advantages/Disadvantages to the Elm When the trees are felled are part of the coppice cycle, suckers grow into a circle of new elms called a clonal patch. The patch puts out new suckers and continues to expand. The elm responds to fungal diseases such as Dutch elm disease by growing root suckers. However, they become infected too and die. They have no resistance to the fungal attack, as there is no genetic variation. Natural selection cannot occur.

Artificial Vegetative Propagation The two main methods of artificial vegetative propagation are: Taking Cuttings. Grafting. Read the top of page 154 and summarise the two methods above.

Artificial Vegetative Propagation The two main methods of artificial vegetative propagation are: Taking Cuttings. Grafting. .

Large-Scale Culturing using Tissue Culture More modern methods are required to generate huge numbers of genetically identical plants. Only small amounts of a parent plant are required. Valuable plants can be cloned quickly.

Task Add information to your handout on Tissue Culturing using pages 154-155 of the textbook. Include advantages and disadvantages

Learning Objectives Understand what clones are. Understand the advantages and disadvantages of asexual reproduction. Understand what natural vegetative propagation in plants is.