Not sure what you mean by "completely genetic".  What cause other than
genetic would "handedness" be due to?

Paul M.

> ----------
> From:         Charles L Powell
> Reply To:     Conchologists List
> Sent:         Thursday, January 6, 2005 10:07 AM
> To:   [log in to unmask]
> Subject:      Foram "handedness" was Re: fake shells... the Cebu Shell
> Daktari strikes!
>
> Not directly mollusk related, but planktonic foraminiferal "handedness"
> may
> be completely genetic as the different "forms" are now being assigned to
> different species.  See Kucera, M., and Kennett, J.P., 2000, Biochronology
> and evolutionary implications of late Neogene California margin planktonic
> foraminiferal events:  Marine Micropaleontology, v. 40, p. 67-81.
>
> Best,
>
> Chuck
>
> Charles L Powell, II
> Western Earth Surface Processes Team, MS 975
> U. S. Geological Survey
> 345 Middlefield Rd.
> Menlo Park, CA  94025
> [log in to unmask]
> (650) 329-4985
>
>
>
>                       Andrew Grebneff
>                       <[log in to unmask]        To:
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>                       TAGO.AC.NZ>                        cc:
>                       Sent by: Conchologists List        Subject:  Re:
> fake shells... the Cebu Shell Daktari strikes!
>                       <[log in to unmask]>
>
>
>                       01/05/05 03:58 AM
>                       Please respond to
>                       Conchologists List
>
>
>
>
>
>
>
> >  However, mollusks are relatively unusual in having many kinds that
> >are normally distinctly asymmetric.  Many forminifera have
> >snail-like coiled shells; these can be sinstral or dextral, too.
>
> Foram handedness is temperature-controlled, with no genetic
> component, and is unrelated to gastropod coiling. Indeed, the
> organisms (currently in kingdom Protists, so they are not animals or
> "creatures") themselves are basically "amorphous" blobs of protoplasm
> & organelles. I wonder how they manage to secrete such regular and
> beautiful shells?
>
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