genetics isn't always simple (or beautiful), but dominance designations help
talbert at U.WASHINGTON.EDU
Mon Sep 20 23:03:12 EST 1993
As a former fly guy who worked on genes with both dominant and
recessive alleles, some of which showed intragenic complementation and
most of which showed partial penetrance, I would like to voice my
enthusiastic "backward looking" support for some form of dominance
designation. (And this despite the fact that the nomenclature of my
alleles was changed two or three times as fads in designating dominance
and reversion relationships, which haven't been discussed here yet, came
The numerous complications in dominance relationships which have
been listed on this network can all occur, but in practice they are fairly
rare. It is precisely in the complicated cases where an optional dominance
designation such as the ones suggested by Rich Jorgensen or the C. elegans
system would be most useful to the uninitiated reader as an aid to
following complex crosses. Databases are very valuable and should be
consulted by those who want to know more, but it is very helpful to be
able to figure out how someone did a cross in the paper you are reading on
the bus on the way home from work without having to consult a database.
New people in the field will learn the nomenclature rules fairly quickly,
but will never know enough particulars about other people's alleles to
navigate painlessly through crosses outside their immediate area without
simple aids such as dominance indicators.
The optional fields idea, in which a set of defined abbreviations
can be added (when helpful) to the basic gene designation to convey pertinant
information such as dominance, temperature sensivity, or allele of origin
for revertants, seems to me as ideal as these nomenclature systems get.
Codominance could be indicated by marking both alleles dominant or with a
special designation. While it may not be possible (or desirable) to have
designations which anticipate the nuances of every complex case, a few
common designations such as dominance would be extremely helpful for the
vast majority of uncomplicated cases and many complex ones, particularly if,
as I dare to dream, we someday have commonly used balancer chromosomes with
Simplicity of designation is important, but only as an aid to
simplicity of understanding.
P. S. Far more complications can arise for phenotypic
designations (currently only indicated by "Mut" for a gene "mut") when, as not
too infrequently happens, different alleles of the same gene have
significantly different phenotypes. Could there be a shorthand way of
indicating "the phenotype of the specific allelic combination mut-1/mut-2"?
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