One of the many things that makes Icelandic sheep so intriguing to me is the many distinct colors and patterns they can come in.   An extensive study was done in Iceland by Professor Stephan Adelsteinsson, in regards to the color and pattern genetics in Icelandic sheep in Iceland.   Dr. Phil Sponenberg, also a color genetics specialist that has worked with Stephan Adelsteinsson, has done an in depth study on the theory of color and pattern genetics in all sheep.  I was fortunate enough to be able to attend one of his classes.

You can find an article written by both Phil Sponenberg and Stephan Adalsteinsson PhD along with other genetic sheep specialists in a book called, "Colored Sheep and Wool" by Kent Erskine which is from the proceedings of the world congress on colored sheep U.S.A 1989.   Stefan Adalsteinsson also wrote a book called, "Color inheritance in Icelandic Sheep and relation between color, fertility and fertilization" published by, "Journal of Agricultural Research in Iceland".   Unfortunately, I believe this book is now out of print.

Between Professor Stephan Adelsteinsson and Dr. Phil Sponenberg studies on colored sheep,  I have taken their combined information and developed this page to help make is easier to understand  the color and pattern genes and their order of dominance. Once you understand the basic concept, then the fun begins in laying out your own breeding combinations for your next lambing season.

Because of so much interest in colored sheep and the study of color genetics, sheep breeders with other breeds of sheep are now looking at the Icelandic color and pattern study and applying it to their own breeding program.  

 

How the color and pattern gene theory works in Icelandic sheep: Each parent carries 2 color genes, 2 pattern genes, and 2 on/off switches for spotting.  Each parent then gives 1 each of these to it's offspring. For Example: This Black Dam carries: 2 Color genes   -  1 brown (moorit) & 1 black 2 Pattern genes -  Both solid Spotting, yes or no -  No Our black dam with her twin ewe lambs from the 1998 lambing season. This Grey Ram Sire carries: 2 Color genes   -  1 brown (moorit) & 1 black 2 Pattern genes -  1 grey & 1 solid Spotting, yes or no  -  No   Our grey herd sire, "Big Horns" REX384F The potential offspring from this mating can only be a solid black, a solid moorit, a grey/moorit or a grey/black.  (At this time, it is assumed that each parent does not carry spotting). This is why: Each of these parents carries 1 brown (moorit) color gene and 1 black color gene. The offspring will inherit one of these color genes from each parent.  Although moorit is not visibly seen on either the dam or sire, each one carries a recessive moorit gene as found out by their moorit offspring they produced together.  Each parent carries the solid gene, while the sire also carries the grey gene. As seen in the above photo of the black dam with her 1998 offspring, this breeding combination produced a grey moorit ewe lamb and a solid black ewe lamb which supports the theory of the potential offspring from this mating. Photo's 3 years of breeding this same dam/sire combination: 1999 Lambing Season: A grey/black ewe lamb A solid black ram lamb 1997 Breeding Season: "Champ", our solid moorit herd sire The 1997 offspring from the above dam and sire breeding produced this adult grey/black dam pictured on the right.   The 2 lambs to her left are her offspring from the 1999 lambing season. The sire was a moorit mouflon ram.  Notice the mouflon pattern expressed on middle animal shown in this photo. In summary: Over the 3 breeding seasons with this same dam and sire breeding combination, a total of 6 lambs were born.  The color and pattern combinations are detailed below: # of Offspring produced Pattern  Color  2 Lambs Grey Black 2 Lambs Solid Black 1 Lamb Grey Moorit 1 Lamb Solid Moorit As we mentioned earlier, the potential offspring from this dam and sire mating could only produce a solid black, a solid moorit, a grey/moorit or a grey/black. As you can see from our results above, we were able to achieve all 4 of the total possible pattern combinations from this black dam and grey/black sire breeding combination. Click Here to return to top of page

Patterns In Order of Dominance
(Agouti Locus A)

Locus is Greek for location
Agouti is how the pattern is distributed

Chart Information from Stephan Adelsteinsson book titled "Color inheritance in Icelandic Sheep and relation between color, fertility and fertilization" published by, Journal of Agricultural Research in Iceland.