I in which chromatids appear to repel each other. Altering some specific part of a cloned gene and reintroducing the modified gene back into the organism. A type of selection that removes individuals from one end of a phenotypic distribution and thus causes a shift in the distribution. Selection that changes the frequency of an allele in a constant direction, either toward or away from fixation for that allele . Generations that have no overlapping reproduction.
All reproduction takes place between individuals in the same generation.
A type of selection that removes individuals from the centre of a phenotypic distribution and thus causes the distribution to become bimodal. A graph of some precise quantitative measure of a character against its frequency of occurrence. The fundamental substance of which genes are composed. A section of DNA that has been inserted into a vector molecule, such as a plasmid or a phage chromosome , and then replicated to form many identical copies. See also clone DNA cloning See gene cloning .