|Over the last few years there has been an
upsurge of interest in the genetics of the cat. One result has been
the formation of a committee to review the use of symbols for genes and
to recommend a uniform notation.
The task the committee set itself was threefold--to examine the various
symbols which have been utilized to denote the genes and to ensure that
the symbols do not conflict with those in general use in mammalian genetics.
Finally, to recommend a standard set of symbols for use henceforth.
This has been accomplished and a report has been published in the Journal
of Heredity (Vol. 59, pp. 39-40, 1968).
The recommended symbols are given in the accompanying table. Few
changes have had to be made and the most important are probably the following:
The symbol y has been previously used
for the yellow sex linked gene whereas O
is recommended. The reason is that the symbol y
contravenes the rule that genes with a heterozygous expression should be
given a capital letter. A capital Y
is clearly unsuitable because of confusion with the Y
chromosome. The designation O
had already been employed by Komai as an alternative symbol for the gene
and is now adopted as the standard.
The tabby alleles have been variously symbolized in the past. The
recommended symbols are now Ta,
and tb for the Abyssinian,
striped and blotched tabby respectively. Unfortunately the second
symbol cannot easily be shown with some typewriters; in these cases it
is legitimate to use a plain capital T.
Though, strictly speaking, striped should be used, mackerel could be employed
for one of the tabbies designation as this description is perhaps more
well-known in the fancy. The designation of Abyssinian replaces the
former "lined" since it is considered that the new description is more
apt. Most people are familiar with the Abyssinian tabby as represented
not so much by the exhibition animal but the form with narrow striped on
The gene for complete albinism (pink eyes and white coat) is listed as
provisional because no breeding data have been published, but there is
good reason to suppose that such animals have been seen in the past.
The gene for dominant black discovered by Tjebbes is listed as provisional
because the gene has not been definitely observed since Tjebbes report
A gene producing ruby, reddish or pink eyes combined with a bluish fawn
coat color is known in many animals but not in the cat until very recently.
In 1962 Todd discovered a cat of this general description but the animal
died before leaving viable young. Thus this mutant color is a decided
possibility and a careful watch should be kept for a recurrence.
As yet this gene has not been formally symbolized although the symbol
p is held in reserve for it.
Since the report was sent for publication several other genes and breeding
results have come to hand. The new genes are Fd
for folded ear carriage; hy for a bloated
head anomaly; Wh for wirehair coat;
for Oregon rex; and I for inhibition
of hair melanin. The existence of the gene cch
for silver is now suspect and the phenotype thought to be due to cch
now seems due to gene I.
Crosses between Cornish rex and German rex have revealed that these are
due to identical mutations. Hence the symbol rg for German rex which
had been provisionally proposed by the committee should now be ignored.
||Pink eyed dilute
||piebald white spotting
||Symbols in brackets indicate symbols which are accepted on a provisional