Tetraploid (Gr. Tetraploos - Quadruple)

Tetraploid (Gr. Tetraplos - Quadruple).

A tetraploid is an individual with four sets of chromosomes in each cell (composed of tetraploid cells).

Tetraploidy is the presence in the cells of an organism of not two (as usual), but four haploid sets of chromosomes. Tetraploid cells contain 4 sets of chromosomes instead of two, as in diploid organisms.

Tetraploidy can occur naturally or artificially. Natural tetraploidy is sometimes observed in plants as a result of improper cell division or fertilization by unreduced gametes. Artificial tetraploidy can be caused by treating cells with colchicine, which blocks spindle division during mitosis.

Tetraploid organisms often have large cell and organ sizes and increased resistance to unfavorable factors. Tetraploidy is used in plant breeding to obtain large-fruited varieties.