Natural colored fleeces have such beauty and individuality. Each fleece is unique. Clearly, the genetics that controls fleece color must be rather complex. However, we understand quite a lot about the genes that are behind the wonder of these colored fleeces.
Genes are located on chromosomes. Because chromosomes are paired - one from each parent - every individual has two versions (called alleles) of every gene, one from the dam, one from the sire. The base color of a fleece is determined by the alleles at the black/brown location (B locus). There are two possible alleles here: BB (black) and Bb (brown, or moorit).
Agouti alleles determine the symmetrical pattern of white, or light, areas on the fleece. There are many possible agouti alleles which display varying degrees of dominance over one another. In general the darker the pattern (less white), the more recessive the alleles. The agouti alleles we believe we have identified in our flock are Awt (white/tan), Ab (badger-face), Albf (light badger-face), Alb (light blue), Abl (blue), Adb (dark blue) and Aa (self). The Awt allele is the most dominant and produces an all white sheep. The Aa allele is the most recessive and produces a solid black or brown sheep.
Spotting is controlled by other genes which produce asymmetrical patches of solid white. These can be anywhere on the body and are common on the head, lower legs and tail. They will be superimposed on whatever pattern is set by the agouti genes.
In addition, a dominant allele at the extension (E) locus will produce a solid black or brown animal, indistinguishable from a self (Aa) individual. This is the “dominant black” which has become quite common in many natural colored flocks.
Now for some baby pictures:
A? BB Ed
A? Bb Ed
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