Íslenskar landbúnaðarrannsóknir - 01.03.1970, Page 17

COLOUR INHERITANCE IN ICELANDIC SHEEP ] 5
no such distinction can be made between
them until the animals have reached adult
age, and the present study was mainly con-
cerned with lamb colours.
Colour 06 — greybrown (Plates I, 6 and
II, 3)
This colour is the same as the grey
colour, except that here the pigmented
fibres have brown pigment. This colour is
very variable phenotypically. The same 7
scores as were used for the grey have also
been used for the greybrown colour, the
score 1 being given for the lightest shade
and 7 for the darkest shade.
The lightest type of greybrown is so
similar in colour to the darkest type of tan
at birth that sometimes it might be diffi-
cult to distinguish between the two. This
difficulty did not arise in the present study
because very few greybrown lambs with
the lower scores were born, and those born
came from matings of known nonwhite
parents, so the possibility of white colour
with tan pigment present could be ex-
cluded.
Colour 07 — brown badgerface
(Plate IV, 2)
This colour shows the same pattern as
the black badgerface, and the only differ-
ence is that the pigment in brown badger-
face animals is brown. This colour sliows
lillte variation and is easy to classify, but
care has to be taken if greybrown badger-
face could be expected, see colour 13 be-
low.
Colour 08 — brown mouflon
(Plate III, 4)
This colour, called brown reversed
badgerface by Roberts and White (1930a),
is the same as black mouflon, but with
black pigment replaced by brown. This
colour shows little variation and is easy to
classify. One thing which should be point-
ed out in connection with colours 07 and
08 is that due to the fact that these colours
have brown pigment, any rustred agouti-
bands will be more or less disguised, when
the basic colour is brown. The same will
happen to tan fibres which might occur
on the upper part of the body in colour
07. The might mistakenly be classified as
brown fibres.
Colour 09 — brown (Plate I, 4)
This colour produces only brown fibres
on the animals and no white fibres are
found anywhere on the animal at least
during the first few weeks after birth. The
same greying with age as described for the
black colour may occur in the brown
colour.
Pálsson (1944) describes two types of
brown in Icelandic sheep, darkbrown and
lightbrown, but no such distinction be-
tween brown colours has been attemptecl
in the present study. Some phenotypic
variation in the brown colour has been
observed, however, but so far no conclu-
sive evidence of two distinct classes of
brown colour has been obtained.
Colour 10 — grey badgerface
(Plate II, 4)
This colour combines the effect of the
badgerface pattern with the eifect of the
grey jtattern in animals with black pig-
ment. The combined effect is such that
areas witliout pigment in each of the sepa-
rate patterns are also without pigment in
the combined pattern. Similarly areas that
are pigmented in both patterns separately
are also pigmented in the combined patt-
ern, while areas that are pigmented in one
pattern and without pigment in the other
are invariably witliout pigment in the