Tunis are not like most wooled breeds of sheep. When expressing the Awt allele at the agouti locus almost all wool sheep express the w, white. These examples would be Dorsets, Cheviots, Montadales, and Columbias.
Tunis for some reason express the t, tan of the Awt allele. It is unknown why or how Tunis do this. It could be through the extension genes allowing modifications on the agouti gene at the white tan allele. This could also explain the wide range of “Tan” that we can see in the Tunis breed.
So if we were trying to type some Tunis they would be
B?B?, AwtA?, E+E+, S?
The only things that we know for sure
- B?B? The brown black gene is unknown due to the masking from the Agouti gene
- Awt at the Agouti locus
- Since Awt is completely dominate we do not know what the other allele is at the Agouti locus
- E+E+ the extension gene is letting the Agouti gene express pattern
- S? at the spotting gene
- Since no spotting is dominate we do not know what the other allele at the spotting locus is
This could mean that we could have Tunis floating out there with recessive alleles at the Agouti gene that are unfavorable. If you were to breed two of these sheep together it is possible it get one of the non Awt (Tan) sheep. For example:
|Ab Ag(grey & badgerface)
It is also possible to have spots, since no spots is dominate.
|Non→ spotted ↓