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homologous

 - 6 dictionary results

ho⋅mol⋅o⋅gous

[huh-mol-uh-guhs, hoh-]
–adjective
1. having the same or a similar relation; corresponding, as in relative position or structure.
2. corresponding in structure and in origin, but not necessarily in function: The wing of a bird and the foreleg of a horse are homologous.
3. having the same alleles or genes in the same order of arrangement: homologous chromosomes.
4. Chemistry. of the same chemical type, but differing by a fixed increment of an atom or a constant group of atoms: Methyl and ethyl alcohols are homologous.
5. Immunology. pertaining to an antigen and its specific antibody.

Origin:
1650–60; < ML homologus < Gk homólogos agreeing, equiv. to homo- homo- + -logos proportional, equiv. to log- (s. of lógos proportion; see logos ) + -os -ous
Dictionary.com Unabridged
Based on the Random House Dictionary, © Random House, Inc. 2009.
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ho·mol·o·gous   (hə-mŏl'ə-gəs, hō-)   
adj.  
  1. Corresponding or similar in position, value, structure, or function.

  2. Biology Similar in structure and evolutionary origin, though not necessarily in function, as the flippers of a seal and the hands of a human.

  3. Immunology Relating to the correspondence between an antigen and the antibody produced in response to it.

  4. Genetics Having the same morphology and linear sequence of gene loci as another chromosome.

  5. Chemistry Belonging to or being a series of organic compounds each successive member of which differs from the preceding member by a constant increment, especially by an added CH2 group.


[From Greek homologos, agreeing : homo-, homo- + logos, word, proportion; see leg- in Indo-European roots.]
The American Heritage® Dictionary of the English Language, Fourth Edition
Copyright © 2009 by Houghton Mifflin Company.
Published by Houghton Mifflin Company. All rights reserved.
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Word Origin & History

homologous 
1660, from Gk. homologos "agreeing, of one mind," from homos "same" (see same) + logos "relation, reasoning, computation," related to legein "reckon, select, speak" (see lecture).
Online Etymology Dictionary, © 2001 Douglas Harper
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Medical Dictionary

Main Entry: ho·mol·o·gous
Pronunciation: hO-'mäl-&-g&s, h&-
Function: adjective
1 a : having the same relativeposition, value, or structure: as (1) : exhibiting biological homology (2) : having the same or allelic genes with genetic loci usually arranged in the same order<homologous chromosomes> b : belonging to or consisting of a chemical series whose members exhibit homology
2 a : derived from or involving organismsof the same species <homologous tissue grafts> —compare AUTOLOGOUS, HETEROLOGOUS 1 b : relating to or being immunity or a serum produced by or containing a specific antibodycorresponding to a specific antigen —ho·mol·o·gous·ly /-lE/ adverb
Merriam-Webster's Medical Dictionary, © 2002 Merriam-Webster, Inc.
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Medical Dictionary

homologous ho·mol·o·gous (hə-mŏl'ə-gəs, hō-)
adj.

  1. Corresponding or similar in position, value, structure, or function.

  2. Similar in structure and evolutionary origin, though not necessarily in function.

  3. Relating to the correspondence between an antigen and the antibody produced in response to it.

  4. Having the same morphology and linear sequence of gene loci as another chromosome.

  5. Belonging to or being a series of organic compounds each successive member of which differs from the preceding member by a constant increment, especially by an added CH2 group.

The American Heritage® Stedman's Medical Dictionary
Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.
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Science Dictionary
homologous   (hə-mŏl'ə-gəs)  Pronunciation Key 
  1. Similar in structure and evolutionary origin but having different functions, as a human's arm and a seal's flipper.

  2. Being one of a pair of chromosomes, one from the female parent and one from the male parent, that have genes for the same traits in the same positions. Genes on homologous chromosomes may not have the same form, however. For example, one chromosome in a pair of homologous chromosomes may contain a gene for brown eyes, and the other a gene for blue eyes. Human females have 23 pairs of homologous chromosomes (including the two X chromosomes), while human males have 22 because the Y chromosome is not paired.

  3. Belonging to or being a series of organic compounds, each successive member of which differs from the preceding member by a constant increment, especially by an added CH2 group. The alkanes (methane, ethane, propane, and others) are a homologous series of compounds.

  4. Involving organisms of the same species, as in grafted body tissues.


The American Heritage® Science Dictionary
Copyright © 2002. Published by Houghton Mifflin. All rights reserved.
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