Variation in Chromosome Number

Prime objective of this lecture is to present on Variation in Chromosome Number. Changes in chromosome number can occur by the addition of all or part of a chromosome (aneuploidy), the loss of an entire set of chromosomes (monoploidy) or the gain of one or more complete sets of chromosomes (euploidy). Nullisomy – loss of one homologous chromosome pair. (e.g., Oat); Monosomy – loss of a single chromosome (Maize); Trisomy – one extra chromosome. (Datura) and Tetrasomy – one extra chromosome pair.