A Database for Triticeae and Avena
I.10. Remarks to the proposals and comments on genetic symbolization,
etc. in BGN, Vol. 1.
The following remarks are in the order of your Proposals:
(1) No comment.
(2) 1. I agree with Hagberg and von Wettsetin to consider English and
Latin (inclusive Latinized Greek) as languages of high internationality.
It would be highly unreasonable to change, e.g., albina, agropyroides,
chlorina, deficiens, eceriferum, erectoides, virescens, xantha. The use
of Latin should be possible also in the future. Also your suggestion to
symbolize genes for disease resistance by the Latin genus and species names
of the parasite supports this opinion.
2. Symbols should primarily be as short as possible.
Therefore, triple letters for new symbols should not be obligatory but
may be used if appropriate and wanted by the author.
3. I can not find the case cited by H. & W. to
be a weighty argument against your proposal. With pleiotropic effects,
the most striking character should be considered for the decision on dominance
or recessivity, e.g. the dense spike in erectoides mutants; in some cases
this decision must necessarily be rather arbitrary, of course.
The changing use of capital resp. small letters, just as the special
case of segregation may be, should not be admitted. Each allele should
be given a definitive symbol.
I plead for your suggestion that the capital letter symbol should be
used to designate the phenotype of the original variety, if genes exhibit
clearly incomplete dominance. This is, however, practicable with mutants
only; in other cases, where no original variety or the like can be fixed,
the decision may be rather arbitrary.
4. All letters and numbers should be written on one
line. Superscripts and subscripts should not be used, since they are troublesome
not only in programming some types of computers, but also in good old typewriting
5. Before designating wild type alleles one has to
know what the wild type is. It is easy, of course, with mutants. But what
to do with V/Vt/Vd/v!, Ddt/ddt, Bt/bt,
Ea/ea, S/s, Sh/sh, and the many resistant/susceptibility
genes. Therefore, we need as a prerequisite the agreement on a definitive
wild type, which perhaps would be desirable though not easy.
6. The proposal of H. & W. to accept both systems
should, in my opinion, be followed. Of course, your proposal for the purpose
of standardization is indeed absolutely evident, especially since the former
Ml-a etc. symbols are now being changed (first to Pml etc.,
now obviously to Egl etc.). However, I comprehend when the Swedish
group defends against the resymbolization of their truly numerous mutants,
especially as their system also conforms to the general international rules.
Therefore, one should make the special concession to them to retain their
system. This seems to be the only practicable compromise.
However, in order to make the two systems as similar as possible I would
like to suggest to use neither superscripts nor subscripts on the one side
and to use a hyphen between the basic symbol and the special locus number
or letter, resp., on the other side, e.g.:
Ms2, Eg-ld etc. or ert-r52 etc.
(ms-2 and Egld is a discussible alternative, but not ertr52.)
The willingness for these little changes may be expected of all colleagues,
7. No definite opinion. I doubt whether the objection
by H. & W. is heavy, because the use of a slash (/) between the symbols
i, su or en, resp., and the basic character symbol
would hardly give rise to confusion with a fraction in a genic formula.
8. through 13. No comments.
14. It seems to me to be a little odd to designate
extra-chromosomal factors by Ec/ (or Ec-), in the same way
like some chromosomal genes, e.g. En/ (or En-). From this
reason mainly, and less because of formal objections as to Rule 11, brackets
should be retained.
(3) No comment.
(4) 1c., 1e., and 3. (first sentence of p. 7): I plead completely for
H. & W.'s suggestions.
(5), (6), (7) No comments.
(8) I would like to ask you the question whether it is truly suitable
to give the centromeres the map position 0. Certainly there are advantages,
but also disadvantages, inclusive the difficulties to locate the centromeres
exactly enough and within a reasonable space of time in the future. Why
are barley maps to be handled otherwise than the chromosome maps of such
well-studied organisms like Drosophila, maize, and tomato?
(9) No comment.
(Additional suggestions, pp. 8-10):
1. The suggestion by H. & W. should be followed.
From my person, however, there is no objection against your proposal.
2. No comment.
3. At the end of their comments, Hagberg and von
Wettstein touch upon an important problem, viz. the necessity to establish
the identity of loci between the mapped "classical" genes and the newly
identified mutant genes. This is relevant, however, not only to chlorophyll
deficiency genes but also to others.
As is well known, for a number of the Swedish mutant groups new symbols
have been introduced. These symbols indeed conform to the general international
rules just as the "classical" ones and are also well descriptive. However,
they were established unfortunately without any reference to the long ago
established symbols for the same characters, e.g.:
ert - l; cer - ge, gl, gs;
mat - ea; alb - a, xan - x
Now this situation is a matter of fact, especially since the Swedish
mutant material has been and is being studied so extensively. So far the
identity of mutant and previously known loci has been tested in only few
cases, so that at present both system still can exist side by side without
major mutual trouble. But what to do in the future, when allelism tests
will have increased? Which symbol for a special locus is then to be deleted,
the new one or the old one? Should then be applied the principle of priority,
or of the size of material? Or should rather already now be decided whether
only one, the old or the new basic symbol for a group of polymeric genes
is to be valid? I feel, this problem must be solved now, and it can be
solved only by a reasonable compromise to be settled primarily between
your American and the Swedish group. Only then one can expect that a revised
system will be followed everywhere and for a long future.
BGN 2 toc
BGN Main Index