In microbiology a clone is a group of cells, organisms or DNA molecules that originate from a single ancestor and are genetically identical copies of that ancestor.
Explanation
When a microbial cell divides by binary fission, its daughter cells contain the same genetic information as the parent cell. If those offspring continue to divide without mutation or gene transfer, they produce a population of identical descendants known as a clone. Rapid cell division means clonal populations can grow into visible colonies on solid media. Cloning can also refer to the laboratory process of isolating a single cell or DNA sequence and allowing it to replicate to generate large numbers of identical copies. Molecular cloning involves inserting a DNA fragment into a vector such as a plasmid and introducing it into a host bacterium; the host replicates the vector and thus the inserted gene. T lymphocytes and B lymphocytes in vertebrates expand clonally when they encounter an antigen, producing many identical cells with the same receptor. In nature, many multicellular organisms produce clones through asexual reproduction such as budding, vegetative propagation or parthenogenesis.
Uses and examples
Identifying clones helps microbiologists study mutation rates and genetic variation. A single colony on an agar plate represents a clonal population; researchers may pick a colony to obtain a pure culture. Molecular cloning is fundamental for producing recombinant proteins, vaccines and genetically modified organisms. The term also describes organisms like hydra and yeast that reproduce by budding to form clonal populations. In everyday language, cloning has been applied to animals such as Dolly the sheep, though the concept of identical copies is the same.
Clonal populations highlight how asexual reproduction can preserve genetic information across generations, and clonal expansion is a key principle in immunology and biotechnology.
Related Terms: cloning, asexual reproduction, genetically identical, colony, cell culture