interspecific hybridization (two different species). The resulting hybrid will usually be infertile as the chromosomes cannot pair because they come from different species. But if cells from this hybrid undergo mitotic non-disjunction in tissues which ultimately give rise to gametes, then gametes can be produced. Go back to your notes on our example of Spartinia maritima (Europe 2N= 60) and S. alternifloris (N.A. 2N = 62). Interspecific hybridization coupled with non-disjunction may account for the widespread occurrence of polyploid plants. Estimates say that 25% to 50% of all plant species are polyploid. e,g, wheat, oats, cotton, tobacco, potatoes. Probably also occurs in animals (e.g. salmon is tetraploid) but it is difficult to show.