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From: dgary@ecsvax.UUCP (D Gary Grady)
Newsgroups: net.bio
Subject: Re: Identical twins and handedness
Message-ID: <295@ecsvax.UUCP>
Date: Thu, 22-Aug-85 12:52:49 EDT
Article-I.D.: ecsvax.295
Posted: Thu Aug 22 12:52:49 1985
Date-Received: Sun, 25-Aug-85 06:16:17 EDT
References: <233@drutx.UUCP> <289@ecsvax.UUCP>
Organization: Duke U Comp Ctr
Lines: 19

A recent article in SCIENCE (18 Aug 85) indicates left-handed and
ambidextrous persons have a larger corpus callosum than right-handers.
The corpus callosum is the structure that connects the hemispheres.  One
possibility is that in left-handers and the ambidextrous, brain function
is not as specialized between the two hemispheres of the brain, so more
interhemispheric communication is needed.  This would suggest that in
twins with different handedness, their brains would be quite
significantly different.

Nature-vs-nurture studies involving twins have tended to assume
identical twins have the same "nature" (so any observed difference
would presumably be due to environmental factors).  If it is true that
identical twins tend to have different handedness, this assumption may
be invalid.
-- 
D Gary Grady
Duke U Comp Center, Durham, NC  27706
(919) 684-3695
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