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Help! Definiition of superfamily, family, subfamily

Keith Robison robison at nucleus.harvard.edu
Sun Mar 10 22:30:30 EST 1996

John Hogenesch (john at pc029.pharm.nwu.edu) wrote:
: Molecular evolutionary biologists,
: 	I'm writing a paper where we identify five new members 
: of a gene family.  This brings the total number of identified 
: proteins in vertebrates to eight.  In addition there are five 
: Drosophila members of this family and one bacterial.  What 
: characteristics would make these proteins a superfamily, family, 
: or subfamily?  They all contain a conserved domain, and all but 
: two contain a second domain shared by bunches of proteins.  The 
: splicing patterns of a couple of these proteins have been 
: determined, and they are also conserved (in the conserved 
: domains).  
: 	Any insight would be appreciated, as I can't seem to 
: find a cogent definition of these terms.  I get the feeling 
: people throw them around a lot.

I doubt you'll find a really clear delineation of these --
there is obviously a continuum of similarity from unrecognizable
to identical.  I would tend to just call the largest recognizable
grouping a family, and any subdivisions of that subfamilies, 
unless there is prior precedent for naming things differently.

Probably your best bet is to go to Margaret Dayhoff's writings,
since I think she originally defined the term "superfamily".

Good luck.

Keith Robison
Harvard University
Department of Molecular & Cellular Biology
Department of Genetics 

robison at mito.harvard.edu 

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