What does euploid mean?
Euploid is a technical term in genetics describing a cell or organism whose chromosome number is an exact multiple of the haploid number for its species. In humans, for example, a euploid cell has either 23 chromosomes (haploid, as in gametes) or 46 chromosomes (diploid), with no extra or missing chromosomes. The word carries an inherently positive connotation in clinical settings: a euploid embryo is chromosomally normal and more likely to result in a successful pregnancy. Its opposite is aneuploid, meaning a chromosome count that deviates from this standard. Euploid appears most often in cytogenetics, prenatal screening, and reproductive medicine, where preimplantation genetic testing classifies embryos as euploid or aneuploid before transfer. Though rarely heard outside scientific contexts, it has become increasingly familiar to patients navigating fertility treatment, and it exemplifies how precise Greek-derived terminology allows biologists to describe chromosomal states unambiguously.
adjectiveHaving a chromosome number that is an exact multiple of the haploid number for the species; possessing a complete, balanced set of chromosomes.
- (of a cell or organism) Having a chromosome number that is an exact multiple of the haploid number characteristic of the species.
"The embryo was confirmed to be euploid after preimplantation genetic testing."
"Only euploid embryos are typically selected for transfer in modern IVF cycles."
"The researchers compared gene expression between euploid and aneuploid cell lines."
In IVF clinics worldwide, 'euploid' is the single word every hopeful parent longs to hear — it means the embryo's chromosomes are exactly right.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of euploid
Euploid derives from the Greek prefix eu-, meaning 'good' or 'true', combined with -ploid, from Greek ploos ('fold') via the modern scientific suffix denoting chromosome sets. It was coined in early 20th-century cytogenetics alongside related terms such as haploid, diploid, and polyploid, all of which share the same Greek root. The prefix signals a 'proper' or 'true' complement of chromosomes, in contrast to aneuploid, whose prefix an- indicates deviation.
How euploid is actually used
A technical term used chiefly in genetics, cytogenetics, and reproductive medicine. It is generally confined to scientific and clinical registers and is uncommon in everyday speech.