Polyploidy may occur because of abnormal cell division throughout metaphase I in meiosis. It is most often found in plants.
Polyploidy takes place in some animals, including salmon, salamanders and goldfish, however is especially common between ferns and flowering plants, including both cultivated and wild species.
Polyploidy also takes place normally in some animal tissues, for example human muscle tissues. This is referred to as endopolyploidy.
Polyploidy could be induced in plants and cell cultures by several chemicals: the best known is colchicine, which can lead to chromosome doubling, though its use might have other less obvious consequences as well. Oryzalin will also double the current chromosome content.
Polyploidy is pervasive in plants and a few estimates recommend that 30 to 80% of living plant species are polyploid and numerous lineages show proof of ancient polyploidy within their genomes. Massive explosions in angiosperm species diversity seem to have coincided with the timing of ancient genome duplications shared by numerous species.
It has been established that fifteen% of angiosperm and thirty one% of fern speciation activities are accompanied by ploidy improve. Polyploid plants can come up spontaneously in nature by a number of mechanisms, such as mitotic or meiotic failures and fusion of unreduced (2n) gametes. Both allopolyploids (e.g. wheat, canola and cotton) and autopolyploids (e.g. potato) can be found among both domesticated and wild plant species.
You can find few naturally taking place polyploid conifers. One instance is the Coast Redwood Sequoia sempervirens, which is a hexaploid (6x) with 66 chromosomes (2n = 6x = 66), even though the origin is unclear.
True polyploidy hardly ever occurs in humans, even though polyploid cells take place in highly differentiated tissue, including heart muscle and liver parenchyman and in bone marrow. Aneuploidy is more common.
Polyploidy takes place in humans in the type of tetraploidy with 92 chromosomes (sometimes called 92,XXXX) and triploidy, with 69 chromosomes (sometimes known as 69,XXX). Triploidy, usually because of polyspermy, occurs in around 2 to 3% of all human pregnancies and ~15% of miscarriages.
The huge majority of triploid conceptions finish as a miscarriage; those that do survive to term usually die shortly after birth. In some instances, survival past birth may take place longer if there is mixoploidy with both a triploid and a diploid cell population present.