Íslenskar landbúnaðarrannsóknir - 01.03.1970, Page 29

COLOUR INHERITANCE IN ICELANDIC SHEEP 27
These animals were purchased in autumn
1959 from private flocks in Southern Ice-
land. Arrangements were made with a pri-
vate farmer in the area at a farm called
Skeidháholt to manage the flock and keep
close record of all the sheep, under the
supervision of the author. This flock was
maintained at the same size on the sante
farm until autumn 1963, when it was dis-
persech
In the foundation flock, 23 of the ewe
lambs were grey mouflon and 2 grey
badgerface.
Three of the ram larnbs were grey mou-
flon, and one grey badgerface. A fifth ram
lamb which was also purchased was black
with a white head spot, white collar and
stockings (colour 0562). The last ram was
purchased in order to investigate the in-
heritance ol the white collar. It was also
expected that several homozygous black
mouflon animals would be produced in
the course of the experiment, and if the
black mouflon pattern and the white
collar could be combined in the same ani-
mal, the resulting skin woukl have white
edges and be otherwise black, a colour
which might be of sorne commercial value
in skins used for decorative purpose as
rugs. This goal was not, however, achieved
during the course of the experiments.
The first lambs thought to be homo-
zygous grey out of this flock were obtain-
ed in spring 1960, when 3 grey ewe lambs
were born, 2 of them very liglitgrey, and
one darkgrey.
The 2 lightgrey ewe lambs were so light
coloured that their pelts were of no value
for the fur trade. These lambs indicated
that the lightgrey animals which often
were obtained in darkgrey X darkgrey mat-
ings would often be homozygous, and that
because of their light colour they would
always have been culled.
The third grey lamb which was of the
desired darkgrey colour and was also
thought to be homozygous indicated that
darkgrey homozygous animals might also
be found. From interviews with farmers
who had ownecl grey mouflon sheep, it
had been learned, however, that two types
of grey mouflon might exist, one in which
the colour was produced by the gene for
grey from one parent and the mouflon
gene frorn the other, and another type
where the grey mouflon pattern was pro-
duced by one gene which had the sum
effect of the other two.
An indication of this was first seen by
the author at a sheep sorting station in
Eastern Iceland in autumn 1959, where a
black ewe with a grey mouflon lamb was
observed. The owner of the ewe informed
him that this lamb was by a grey mouflon
ranr which he owned, and that this ram
sired alternatively black and grey mouflon
progeny when mated to black ewes. As the
owner dicl not keep accurate records of
his sheep, this ram could not be investi-
gated further.
In the autumn 1960 it was discovered
that a grey mouflon ewe on farm 18 had
been mated to a black ram the previous
winter and had produced a grey mouflon
ram lamb. As both the ewe and the lamb
were piebald the grey mouflon pattern was
only found by close inspection.
In order to test the hypothesis that the
dam of the darkgrey ewe lamb born in
1960 at Skeidháholt was a heterozygous
carrier of a gene for grey mouflon pattern
she was rnated to a black ram without
pattern the next year. Then she produced
two grey mouflon progeny.
Three other grey mouflon ewes in the
Skeidháholt flock had been obtained from
the same flock as the ewe described above.
They all proved to be heterozygous carri-
ers of a single gene for the grey mouflon
pattern.
Of the 19 remaining grey mouflon ewes
in the foundation stock at Skeidháholt, 16