molecular species?

John McNeill johnm at ROM.ON.CA
Mon May 20 20:42:42 CDT 1996

On May 20, Detlef Leipe wrote:

>It should read "of a particular organism" not
>"of a particular sequence" in line 4 of the first paragraph.
>Here is the corrected message.
>My apologies,
>   Detlef
>Dear All,
>I would be interested to know if the codes of nomenclature and/or
>common usage requires it that the names of organism have to be
>based on a morphological description.  Assuming that it allows the
>unambiguous identification of a particular organism, could a
>molecular sequence, (be it as a gel, a paper hardcopy or an
>electronic file) become the name bearing type?
>I assume that there might be differences with respect to the acceptance
>of non-morphological data between zoological/botanical nomenclature
>on the one hand and bacterial nomenclature (and practice) on the
>other.  Would anybody be able to comment on this?
>Thanks in advance
>  Detlef Leipe
>------------- End Forwarded Message -------------

So far as the Botanical and Zoological Codes of Nomenclature are
concerned, there is unanimity on this issue.  Neither Code is
concerned with the criteria by which taxonomic groups (taxa) are
determined; both deal with the procedures for determining the correct
name for a taxonomically distinguishable group (e.g. a species)
regardless of the criteria involved in making the taxonomic judgement.

So, from the standpoint of nomenclature, it does not matter whether
the species is discriminated by the shape of the hairs on the
antenna/style or by a particular molecular sequence, if someone wishes
to recognise it, the taxon may be named.  The [name-bearing] type
would, however, be the animal or plant designated by the author as
possessing that sequence (or those hairs), not the character itself,
whether sequence or hairs.

Usage is another matter; my impression is that bacteriologists and
virologists would regard discrimination solely by a molecular sequence
as routine, whereas most zoologists and botanists would expect some
[micro]morphological feature to be correlated with the molecular
feature, making practical recognition easier.

John McNeill

From: John McNeill, Director, Royal Ontario Museum, 100 Queen's Park,
      Toronto, Ontario, M5S 2C6, Canada.
      Tel.: 416-586-5639      Fax: 416-586-8044
      e-mail: johnm at

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