(genetics) The chromosomal variation in the normal complete set of chromosomes in a cell or an organism resulting in a multiple of the haploid or basic number of chromosomes
Euploidy is a chromosomal variation that involves the entire set of chromosomes in a cell or an organism. Euploidy is more tolerated in plants than in animals. There may be a single set (monoploidy), two sets (diploidy), or multiple sets (polyploidy, i.e. triploid, tetraploid, pentaploid, hexaploid, etc.) of chromosomes. Other types of euploidy are autopolyploidy and allopolyploidy. In autopolyploidy, there is an additional set of chromosomes, which may be from a parent or identical parental species (i.e. a single taxon). The cell or organisms in autopolyploid condition is called an autopolyploid. Natural autopolyploids are Tolmiea menzisii (piggyback plant) and Acipenser transmontanum (white sturgeon). In allopolyploidy, the additional set of chromosomes comes from another species (i.e. from two or more diverged taxa). The cell or the organism in allopolyploidy state is referred to as allopolyploid. Wheat is an example of an allopolyploid with six chromosome sets.