haploid

1 of 2

adjective

hap·​loid ˈha-ˌplȯid 

: having or involving one set of homologous chromosomes

haploid plant spores

Among animals, the haploid phase is generally restricted to unicellular gametes, which do not undergo further mitoses, followed by gamete fusion leading to a diploid phase, which occupies essentially the entire lifespan of the organism.

—Sarah P. Otto and Aleeza C. Gerstein

compare diploid

haploidy

ˈha-ˌplȯi-dē 

noun

haploid

2 of 2

noun

plural haploids

: a single cell, individual, or generation characterized by a single complete set of chromosomes

Haploids, derived from diploid plants, are generated from gametes of only one parent having a single copy of each chromosome.

—Maria Jose Gonzalo et al.

Examples of haploid in a Sentence

Recent Examples on the Web

Adjective

Asexual whiptails have a special trick for making spermless reproduction work: The egg cells in other animals first double their choromosomes once and then divide twice, leaving them as haploid cells, with half the normal number of genetic material. —Discover Magazine, 13 Feb. 2012

Additionally the haploid nature of mtDNA means that genetic drift is far more powerful in buffeting gene frequencies and introduced stochastic fluctuations, which eventually obscure past mutational signals through myriad mutations. —Razib Khan, Discover Magazine, 19 Apr. 2011

Recently, molecular studies on the basis of disease-causing mutations and haploid DNA markers (i.e. mtDNA and Y-chromosome) supported the linguistic view. —Razib Khan, Discover Magazine, 9 Dec. 2012

This year, a team led by the Hebrew University of Jerusalem finally produced haploid human embryonic stem cells by forcing unfertilized egg cells to divide. —Jonathon Keats, Discover Magazine, 18 Dec. 2016

By rapidly screening many of them, the researchers could isolate cells that stayed haploid after division — about 1 in 1,000. —Jonathon Keats, Discover Magazine, 19 Dec. 2016

In 2001, Dr. Gianpiero Palermo of the Weill Medical College at Cornell University in New York announced that his team created artificially haploid eggs by borrowing techniques from cloning. —Brian Alexander, WIRED, 1 Dec. 2005

This year, a team led by the Hebrew University of Jerusalem finally produced haploid human embryonic stem cells by forcing unfertilized egg cells to divide. —Jonathon Keats, Discover Magazine, 19 Dec. 2016

Noun

By rapidly screening many of them, the researchers could isolate cells that stayed haploid after division — about 1 in 1,000. —Jonathon Keats, Discover Magazine, 18 Dec. 2016

Word History

Etymology

Adjective

derivative of haploid entry 2, after German haploidisch

Noun

borrowed from German Haploid, from Greek haplo- haplo- + German Id "(in August weismann's theory of heredity) the aggregate of determinants (the primary hereditary constituents in germplasm)," short for Idioplasma "part of protoplasm transmitting hereditary properties" (from idio- idio- + -plasma -plasm)

Note: The terms haploid and diploid entry 2 have conventionally been taken as derivatives with borrowed outcomes of the Greek suffix -oeidēs "having the form or appearance of" (Latin -oïdēs—see -oid entry 2)—hence, haplo-/diplo- + -oid. When these words were first introduced, however, by the German botanist Eduard Strasburger (1844-1912), no origin was given: "Schliesslich wäre es vielleicht erwünscht, wenn den Bezeichnungen Gametophyt und Sporophyt, die sich allein nur auf Pflanzen mit einfacher und mit doppelter Chromosomenzahl anwenden lassen, solche zur Seite gestellt würden, welche auch für das Tierreich passen. Ich erlaube mir zu diesem Zwecke die Worte Haploid und Diploid, bezw. haploidische und diploidische Generation vorzuschlagen." ("Typische und allotypische Kernteilung," Jahrbücher für wissenschaftliche Botanik, 42. Band [1906], p. 62; "Finally it would perhaps be desirable that alongside the terms gametophyte and sporophyte, which can be applied only to plants with single or doubled numbers of chromosomes, we should have at our disposal terms also suitable for the animal kingdom. To this end I allow myself to suggest the words haploid and diploid, and respectively haploidic and diploidic generation.") In a subsequent publication ("Die Ontogenie der Zelle seit 1875," Progressus rei botanicae, 1. Band [1907], p. 137), Strasburger made it clear that he had more than the suffix -oid in mind: "In meiner letzten Arbeit über 'typische und allotypische Kernteilung' habe ich vorgeschlagen, die einfachchromosomige Generation als haploid, die doppelchromosomige als diploid zu bezeichnen, wobei Nachdruck auf das 'id' gelegt wird, mit welchem ich an die Bezeichnung Idioplasma von C. Naegeli, Id und Idant von A. Weismann anknüpfe." ("In my last work on typical and allotypic nuclear division, I suggested that generation with one set of chromosomes be called haploid, and with two sets diploid, whereby emphasis was placed on "id," by means of which I link to the terms idioplasm of C. Naegeli and id and idant of A. Weismann.")

First Known Use

Adjective

1906, in the meaning defined above

Noun

1908, in the meaning defined above

Medical Definition

haploid

adjective

hap·​loid ˈhap-ˌlȯid 

: having the gametic number of chromosomes or half the number characteristic of somatic cells : monoploid

haploid noun

haploidy

-ˌlȯid-ē 

noun

plural haploidies