Articles about American Pit Bull Terrier
...to start reading this article from the beginning please click on here...Locus T Pair: Ticking (t) no ticking Research has shown that our breed has only the recessive allele (t) at this locus which in the homozygous recessive (tt) allows no ticking. The dark ticking that we see in our breed is determined on the Locus A series by the dominant (As) allele, not on the Locus T Pair. In some breeds this is known as a sable. In the APBT, traditionally this coloring is called black or brown ticked. There are modifier polygenes that control the location and extent of the black ticking in the breed. The dominant (T) allele at this locus causes the tiny flecks of pigmented hair in otherwise non pigmented (or white) areas. The T allele is typical in breeds such as the English setter and many of the hound breeds. Locus S Series: White Pattern The alleles of the Locus S series produce the white markings that are often seen in our breed. Researchers identify four alleles at this locus: S solid color si Irish spotting sp piebald spotting sw extreme piebald spotting The above sequence reflects the decreasing areas of pigmented hairs. There is some question about the relative dominance of and interaction between the alleles in their heterozygous forms because the expression is complicated by modifier polygenes which affect all of the alleles. Our breed, which research shows carries all four of the alleles, show all ranges of white markings from solid colors to all white. (S)- SOLID COLOR: The homozygous (S) alleles produce a solid colored coat. The modifiers will, on occasion, produce a small amount of white markings on the throat, chest, toes, abdomen and belly.
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