See also reversion . Genetic drift observed in a population founded by a small non representative sample of a larger population. A chromosomal region that has a tendency to break. The most common form of inherited mental retardation. Named for its association with an X chromosome with a tip that breaks or appears uncondensed.
Inheritance involves imprinting.
The insertion or deletion of a nucleotide pair or pairs, causing a disruption of the translational reading frame . Consequently the amino acid sequence of the protein is altered from the point of the mutation to the carboxy terminus. A step curve in which the frequencies of various arbitrarily bounded classes are graphed. Selection of a genotype depending on its frequency in the population . In fungi, the organ in which meiosis occurs and sexual spores are produced.