identical twins

Keith Robison robison at
Fri Jul 5 09:23:51 EST 1996

George Gutman (ggutman at MEDED.MED.UCI.EDU) wrote:
: "Siblings" refers to offspring of the *same* parents, not just 
: genetically identical parents.  The offspring of different mating pairs 
: of inbred mice, for example, are not siblings, despite the fact that they 
: are genetically identical to each other (as well as to their parents, and 
: all other members of the same inbred strain).  So the human offspring in 
: question are certainly not "siblings".

Perhaps what is safest to say is that such offspring are not siblings
but are genetically _indistinguishable_ from sibs.  This might be
a useful property in some contexts.

And BTW, all members of an inbred mouse strain are obviously not 
genetically identical -- there is an obvious bimodal distribution
of genotypes :-)

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

robison at 

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