Aneuploidy is gain or loss of one or more chromosomes, but not a complete set.
- Monosomy is loss of a single chromosome from a diploid genome.
- Trisomy is gain of one chromosome in a diploid genome.
Euploidy is possession of multiples of the haploid set of chromosomes.
Polyploidy is possession of more than two sets:
triploid is three sets and tetraploid is four sets.