Aneuploidy

Part of speech: noun

Pronunciation: /ˈænjʊplɔɪ̯di/

Definitions

1. A genetic condition marked by a non-standard chromosome count, impacting various developmental and health aspects of an organism
2. The presence of an incorrect number of chromosomes in cells, which may give rise to several genetic disorders and affect development
3. A genetic abnormality characterized by an atypical number of chromosomes in cells, potentially leading to various health issues and developmental changes

Etymology: Aneuploidy is built from "an-", a Greek negative prefix meaning "not," plus "euploid," which describes a cell whose chromosomes come in the complete, standard set. So the word literally names a cell or organism that is not euploid, one with an extra or missing chromosome rather than the normal complement. The prefix and the root were both assembled from Greek, as is common in scientific vocabulary. The "euploid" part comes from "eu-," meaning "well" or "true," joined to "-ploid," from the Greek "-ploos," meaning "-fold," which is also found in words like "diploid" and "haploid." Together, "euploid" describes a normal multiple of the basic chromosome set, and aneuploid describes the departures from it. The term is a technical coinage from the twentieth century, created by geneticists who needed precise language for chromosome counts that did not match the standard pattern. Its use in English reflects the cytogenetics research of that era, not any ancient Greek usage.