Íslenskar landbúnaðarrannsóknir - 01.03.1970, Page 109

COLOUR INHERITANCE IN ICELANDIC SHEEP 107
strongly that some badgerface-mouflon ani-
mals may have been obtained in the ex-
periments, and that they would have been
classified as badgerface if they were of the
light type but as mouflon if they were of
the dark type. It also may be assumed that
both the light and dark badgerface-mouflon
types would have been regarded as deviat-
ing considerably from the characteristic
patterns, and that rams of this type would
therefore not have been used. Assuming
this to be the case, all the results obtained
by Roberts and White (1930 a) except two
are consistent with the view that the genes
for badgerface and mouflon are allelic.
The final conclusions drawn by Roberts
and White (1930 a) about the inheritance
of the colours studied were as follows:
“1. White colour depends upon the pre-
sence of an inhibitor, which prevents
the appearance of selfcolour or of the
patterns.
2. If the inhibitor is absent the coat may
be either black or brown. Whether
black is allelomorphic to brown or
not must be left an open question. This
point will be discussed further in this
section.
3. In the absence of the inhibitor the
factor for badgerface jiattern either in
the duplex or sintplex state gives
badger-face. llrown and white badger-
faces liave not yet been obtained but
there is no reason to suppose that they
cannot be produced. If the reversed
badgerface factor is also present, either
in the duplex or simplex state, it pro-
duces no effect; badgerface sheep which
possess in addition the reversed badger-
face factor appear to be indistinguish-
able from badgerface sheep that do
not possess it.
4. In the absence of the inhibitor and
also in the absence of the badgerface
factor, the reversed badgerface factor
in either the duplex or simplex state
turns self-colour into reversed badger-
face.“
Koch (1937) found that the mouflon
pattern was recessive to white.
Berge (1958, 1964 a) has also carried out
experiments which involved crossings of
sheep with the badgerface pattern with
sheep showing the mouflon pattern. In his
experiments the occurrence of animals
showing both patterns has not been re-
corded either, but his conclusion about the
inheritance of the two patterns is that
mouflon is dominant to badgerface, i.e. the
opposite of the conclusion of Roberts and
White (1930 a).
It is clear from Berge’s work, that his
criteria for classification of the patterns
have been somewhat different frorn those
of Roberts (1924) and Roberts and White
(1930 a). Berge (1964 a) regards the occurr-
ence of black belly to be tlie main criterion
for badgerface and that of white belly to
be the main criterion for the mouflon patt-
ern, wliile the typical head pattern in the
badgerface sheep is regarded of minor im-
portance as a classification characteristic, as
it will only be clearly visible in the ligther
badgerface types. Results of crosses between
sheep with the badgerface and mouflon
pattern gave 27 mouflon, 8 badgerface, 6
without these patterns and none showing
both patterns (Berge, 1964 a). A similar
crossing reported by Roberts and White
(1930 a) gave 23 badgerface, 1 mouflon, 1
without both patterns and none showing
both patterns.
Berge (1964 a) gives the percentage of
white fibre in samples taken from the back
of 10—14 days old lambs showing the patt-
erns badgerface, mouflon and grey (skimlet).
The highest and lowest figures for the grey
lambs are 54 ancl 13 per cent white fibres,
respectively, for the mouflon lambs 88 and