- Created by: Claire McMillan
- Created on: 22-05-13 11:21
What are clones?
Genes, Cells, or whole organisms that carry identical genetic material because they are derived from the same original DNA.
Identical twins are produced when a zygote splits into two. These twins are natural clones.
Plants produce asexually, by producing runners, the new plants are clones.
Bacteria divide asexually by binary fission, all resulting bacteria are clones.
All of these processes produce identical clones of the 'original' DNA which generates new organisms with the same cloned DNA.
Distinctions have to be drawn between cloned cells, genes and organisms.
Production of cloned DNA is a natural process for grotwth and reproduction, which can be achieved by artificial means.
reproduction in prokaryotes and eukaryotes
Prokaryotes divide via binary fission. Their DNA replicates, the cell divides in two. If there are no mutations, both cells are genetically identical to each other and the parent.
Eukaryotes reproduce via mitosis. the genetical material replicates and separates to form two new nuclei which contain identical copies of the DNA. in single-celled eukaryotes, the cell divides to form 2 identical daughter nuclei.
In multicelluar eukaryotes, particularly plants, have cells that can grow into new separate organisms with identical DNA to the parent, so they are clones.
Advantages and Disadvantages of asexual reproducti
- It is quick, allowing organisms to reproduce rapidly and so take advantage of the resources in their enivronment.
- it can also be completed if sexual reproduction fails or is impossible, e.g. no mate.
- all offspring have the genetic information to enable them to survive in their environment.
- It does not produce any genetic variety, so any genetic parental weakness will be in all offspring, e.g. Dutch Elm Disease
- If the environment changes, for example with the introduction of a new disease-causing organism, then all genetically identical organisms will be equally susceptible, there will be no mutation to produce an immunity or higher resistance to the disease.
Asexual reproduction in plants takes place naturally in a variety of different ways.
Some plants, including the English Elm tree, are adapted to reproduce asexually following damage to the parent plant. They then survive catostrophies such as burning or disease.
Basal sprouts or root suckers appear within 2 months of the destruction of the parent plant/
They grow from meristem tissue, close to the ground, in the trunk of the parent plant where the least damage is likely to have occured.
Advantages and disadvantages of vegetative propgat
When a tree is felled during the coppice cycle, the root suckers grow in a circle of new elms, called a clonal patch. This in turn produces more suckers, expanding the clonal patch as far as resources permit.
Dutch Elm disease spread throughout Europe's elms. Leaves withered, branches dies, the trunks died. The fungal disease was carried by a bettle. They grew root suckers which became infected after they reached 10cm high as they were identical to the trunk, so carried the disease.
the clonal patch can expand over a long distance, increasing the amounts of survived plants.
Because they are clones, Dutch Elm disease passed from parent plant to root suckers, causing them to become infected.