Polyploid

Polyploid cells are cells containing multiple copies of their chromosomes. This often occurs in plants: wheat, for example, after millennia of hybridization[?] and modification by humans, has strains that are triploid, with three copies of each chromosomne, and tetraploid, with four copies.

Polyploidy can be induced in cell culture by some chemicals: the best known is Colchicine[?], which causes chromosome doubling.

See also : ploidy -- biology -- genetics