chro·​mo·​some | \ˈkrō-mə-ˌsōm, -ˌzōm\

Definition of chromosome 

: any of the rod-shaped or threadlike DNA-containing structures of cellular organisms that are located in the nucleus of eukaryotes, are usually ring-shaped in prokaryotes (such as bacteria), and contain all or most of the genes of the organism also : the genetic material of a virus — compare chromatin

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Other Words from chromosome

chromosomal \ ˌkrō-​mə-​ˈsō-​məl , -​ˈzō-​ \ adjective
chromosomally \ -​mə-​lē \ adverb

Examples of chromosome in a Sentence

Recent Examples on the Web

Over time, these molecules will gradually exchange segments with chromosomes inherited from other individuals. Cyrus Farivar, Ars Technica, "GEDmatch, a tiny DNA analysis firm, was key for Golden State Killer case," 27 Apr. 2018 If an embryo has cells with a missing or extra chromosome it is considered aneuploid, or abnormal, and not recommended for use. Sumathi Reddy, WSJ, "IVF Testing Spurs a Debate Over ‘Mosaic’ Embryos," 21 Mar. 2018 Between a quarter and a half of the cells were aneuploids, typically missing one copy of one chromosome. New York Times, "Every Cell in Your Body Has the Same DNA. Except It Doesn’t.," 21 May 2018 Abnormal embryos — which appear to have the wrong number of chromosomes — are almost universally considered nonviable and discarded by other fertility doctors. Ariana Eunjung Cha, Washington Post, "This fertility doctor is pushing the boundaries of human reproduction, with little regulation," 14 May 2018 Fernando Mendez, a geneticist, and his colleague Carlos Bustamante of Stanford University reported that one of the notable differences between the human and Neanderthal Y chromosomes lies in a gene linked to transplant rejection. Natalie Angier, New York Times, "Secrets of the Y Chromosome," 11 June 2018 Anna, from Louisville, Miss., was born with Prader-Willi syndrome, a chromosome disorder that has also caused her to have a speech delay and some behavioral problems, her mother said. Lindsey Bever, Washington Post, "A 380-pound beauty queen wants to bring attention to a rare disorder that causes constant hunger," 27 Mar. 2018 Cancer cells typically active an enzyme that expands the chromosome ends, getting around this limit. Diana Gitig, Ars Technica, "Naked mole rats have a complicated relationship with cancer," 7 Feb. 2018 Certainly genes are not the determinants: Children with XY chromosomes who lack receptors for testosterone and thus have feminized anatomy — and are in turn socialized as women — all tend to identify as women, despite that Y chromosome. Alex Morris, The Cut, "Is it possible to raise your child entirely without gender from birth? Some parents are trying.," 3 Apr. 2018

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'chromosome.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

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First Known Use of chromosome

1889, in the meaning defined above

History and Etymology for chromosome

borrowed from German Chromosom, from chromo- chromo- + -som -some entry 3

Note: The term Chromosom was first suggested by the German anatomist Heinrich Wilhelm Gottfried von Waldeyer-Hartz in "Ueber Karyokinese und ihre Beziehungen zu den Befruchtungsvorgängen," Archiv für mikroskopische Anatomie, Band 23 (1888), p. 27: "In ester Linier möchte ich mir jedoch den Vorschlag erlauben, diejenigen Dinge, welche soeben mit Boveri als 'chromatische Elemente' bezeichnet wurden, an denen sich einer der wichtigsten Akten der Karyokinese, die Flemming'sche Längsteilung vollzieht, mit einem besonderen terminus technicus 'Chromosomen' zu belegen. Der Name 'primäre Schleifen' passt nicht, da wir bei weitem nicht immer eine Schleifenform für diese Dinge haben. 'Chromatische Elemente' ist zu lang. Andererseits sind sie so wichtig, dass ein besonderer kürzerer Name wünschenswerth erscheint. Plattne… gebraucht den Ausdruck 'Karyosomen'; da dieser aber zu sehr an Kernkörperchen erinnert, dürfte eine andere Bezeichnung vorzuziehen sein. Ist die von mir vorgeschlagene praktisch verwendbar, so wird sie sich wohl einbürgern, sonst möge sie bald der Vergessenheit anheimfallen." ("In the first place I must allow myself to suggest a new technical term, 'chromosomes,' for those things which have been designated by Boveri 'chromatic elements,' at which one of the most important acts of karyokinesis, Flemming's longitudinal splitting, is carried out. The name 'primary loops' is not suitable, since it is by no means the case that these things always have the form of a loop. 'Chromatic elements' is too long. On the other hand, they are so important that a special shorter name seems desirable. Plattner uses the expression 'karyosomes,' but as this too readily brings to mind nucleoli, another name is to be preferred. If the name I propose is serviceable, it will become customary, otherwise it will soon pass into oblivion.")

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Last Updated

10 Nov 2018

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The first known use of chromosome was in 1889

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More Definitions for chromosome



English Language Learners Definition of chromosome

: the part of a cell that contains the genes which control how an animal or plant grows and what it becomes


chro·​mo·​some | \ˈkrō-mə-ˌsōm \

Kids Definition of chromosome

: one of the rod-shaped or threadlike structures of a cell nucleus that contain genes and divide when the cell divides


chro·​mo·​some | \ˈkrō-mə-ˌsōm, -ˌzōm \

Medical Definition of chromosome 

: any of the usually linear bodies of the cell nucleus of eukaryotic organisms, the usually circular bodies of prokaryotic organisms (as bacteria), or especially in some schools of molecular biology the genomes of DNA viruses (as bacteriophages) that take up basophilic stains and contain most or all of the genes of the organism both the chromosomes of cells and those of viruses can duplicate only in the complex environment of a living cell— J. D. Watson an episome, an element that may exist as a free circular plasmid, or that may become integrated into the bacterial chromosome as a linear sequence— Benjamin Lewin

Other Words from chromosome

chromosomal \ ˌkrō-​mə-​ˈsō-​məl, -​ˈzō-​ \ adjective
chromosomally \ -​mə-​lē \ adverb

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More from Merriam-Webster on chromosome

Spanish Central: Translation of chromosome

Nglish: Translation of chromosome for Spanish Speakers

Britannica English: Translation of chromosome for Arabic Speakers Encyclopedia article about chromosome

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to express warning or disapproval

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