tetraploidy

genetics

Written by

The Information Architects of Encyclopaedia Britannica

Last updated

July 14, 2026

Quick Summary

Tetraploidy refers to having a chromosome number that is four times the monoploid number. In genetics, this means an organism possesses four complete sets of chromosomes, rather than the usual two sets found in diploid organisms.1

Polyploidy is a type of chromosomal mutation where entire sets of chromosomes are multiplied. While common in many cultivated plants, such as potatoes (which are tetraploid), it is relatively rare in animals due to potential disruptions in sex chromosome balance.2

Tetraploids can arise from a single species (autotetraploids) or from a combination of chromosome sets from different species (allotetraploids). Polyploids with an odd number of chromosome sets are typically sterile because homologous chromosomes cannot separate properly during sex cell formation.23

Summary created from Britannica articles using AI. AI can make mistakes, so verify using Britannica articles.

3 Britannica Sources

Ask Britannica AI about this topic

Britannica doesn't have a full article on this topic, so we've curated a list of our relevant coverage.

Poaceae
Economic and ecological importance
…diploid (2n), the normal condition; tetraploid (2n = 14, resulting from the fusion of diploid gametes); and hexaploid (2n = 21). An example of a domesticated diploid wheat is einkorn wheat (Triticum monococcum), one of the earliest domesticated wheat species. Hybridization of a diploid wheat with Aegilops speltoides (a closely…
Read More
…diploid (2n), the normal condition; tetraploid (2n = 14, resulting from the fusion of diploid gametes); and hexaploid (2n = 21). An example of a domesticated diploid wheat is einkorn wheat (Triticum monococcum), one of the earliest domesticated wheat species. Hybridization of a diploid wheat with Aegilops speltoides (a closely…
Read More

evolution
Polyploidy
Most polyploid plants are tetraploids. Polyploids with three, five, or some other odd-number multiple of the basic chromosome number are sterile, because the separation of homologous chromosomes cannot be achieved properly during formation of the sex cells. Some plants with an odd number of chromosome sets persist by means…
Read More
Most polyploid plants are tetraploids. Polyploids with three, five, or some other odd-number multiple of the basic chromosome number are sterile, because the separation of homologous chromosomes cannot be achieved properly during formation of the sex cells. Some plants with an odd number of chromosome sets persist by means…
Read More