What does haploidy mean?
Haploidy is the specialized genetics term for the condition of having a single complete set of chromosomes. In a haploid cell, chromosomes are present individually rather than as homologous pairs, although the cell may still contain many chromosomes. The condition is central to the life cycles of many organisms, including fungi, algae, and some plants and animals, and often occurs as one phase of a larger reproductive cycle. Researchers describe haploidy when identifying strains, analysing reproduction, or examining transitions between haploid and diploid states. In organisms such as budding yeast, compatible haploid cells can mate to produce a diploid cell with two chromosome sets. Haploidy is therefore distinct from diploidy and polyploidy, which involve two sets and more than two sets respectively. It is a technical term rather than a general description of anything rare or reduced.
nounThe condition of a cell or organism having a single set of chromosomes, rather than homologous pairs of chromosomes.
- The state or condition of having one complete set of chromosomes.
"The genetic screen confirmed haploidy in the newly isolated strain."
"The genetic screen confirmed haploidy in the newly isolated strain."
"Researchers restored diploidy by mating compatible cells characterized by haploidy."
The plural is grammatically possible but uncommon; haploidy is normally used as an uncountable scientific term.
"The researchers compared haploidies among several related strains."
In many yeasts, two compatible haploid cells can mate and fuse, turning two single-set cells into a diploid with twice the chromosome complement.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Where does haploidy come from?
Haploidy was formed in English from haploid plus the noun-forming suffix -y. The stem comes from Greek háp-los, meaning “single,” combined with the scientific suffix -oid, meaning “form” or “kind.” Related English formations include haplont and haplosome, and the terminology developed alongside modern cytology and chromosome genetics in the late nineteenth and early twentieth centuries.
How haploidy is actually used
A specialized, formal term used chiefly in genetics, cytology, microbiology, and evolutionary biology. It normally describes a cell, organism, generation, or life-cycle phase rather than everyday biological variation.
Easily confused with haploidy
Haploid is the adjective describing an organism or cell with one chromosome set, whereas haploidy names the genetic condition itself.
Ploidy is the general term for the number of chromosome sets, while haploidy specifically denotes the state of having one set.