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Attack of the "logues" - Terminology of logues..... (Apr/03/2005 )

Hi Forumers,

I am perplexed with the use of many words suffixed with logue. There has been a bit of contention within our lab as to when where and how to use it.

there is homologue (I think refers to similar genes within a species), then there is orthologue, and paralogue.

I use homologue for everything....but this is wrong.

Can someone clarify the meanings of homologue, paralogue and orthologue? Also are there any other "logues" I should be aware of?

Thanks in advance.

Nick rolleyes.gif



homology: similarity or identity of a feature in structure or sequence. structures are homologues, if their (not accidentally) similarity or identity is derived by a shared genetic information... homology isn't reall sharply defined, it's more a vague criterium for similarity, often used in phylogenetic context.

orthologues: homologue genes in different organisms that have developed from an single ancestor gene in an ancetor organism, e.g. alpha-globulin genes in different mammals are orthologues.

paralogues: homologue genes in one single organism, that have developed by duplication from a single "ancestor" gene, e.g. alpha-, beta- and gamma- globulin genes in mammals are paralogues.

so, in a way you're right. if you use homologue all the time you're never really wrong, but could be more precice.... biggrin.gif



cheers mike for the clarification!

much appreciated!

Nick smile.gif


there's another -logue.. tongue.gif the analogue

Analogue refers to an entity (be it protein, tissue or organ) which has a comparable structure or function to something else, but is not evolutionary related at all.


that was wonderful, i was also confused about those logues

-shyla Hitesh-