Articles about American Pit Bull Terrier
...to start reading this article from the beginning please click on here...When breeding two dogs with the (bb) genotype, the only resulting combination in the pups would be ( bb) or red nose. Locus C: Pigment depth The Locus C series controls the production of pigment throughout the coat. In dogs, the expression of the Locus C alleles is based on observation rather than experimental studies. The American Staffordshire Terrier breed is felt to have only the dominant (C) allele at this locus. The C allele allows the full expression of color, of dark and light pigments. The allele (cch) or Chinchilla Dilution, found in other breeds at this locus, causes the light pigments to be diluted out in various degrees. This would account for the varying shades found in many littermates depending on their homozygous or heterozygous pairing. The chinchilla dilution allele (cch) does not affect the dark pigment, thus allowing for the white dog with black skin pigment and black nose. Other researchers (Robinson) feel that other modifier polygenes are responsible for this phenotype. CC full-color Ccch medium shade cchcch pale shade Locus D pair: Pigment density (D) intense pigment density (d) dilute pigment density The locus D pair modifies the density of the pigment. The dominant (D) gives full density in both the heterozygous (Dd) or the homozygous (DD) combination. The homozygous recessive (dd) alleles dilute the color. When the dogs basic color is produced by dark pigment, genotype (Bbdd) or (BBdd) yields the color known as blue. The black coat is modified as well as the skin pigment to a gray or blue pigment around the eyes, pads and nose. When the dogs basic color is produced by a light pigment the genotype bbdd (dilute brown pigment) produces a fawn with a silvery cast known in our breed as a fawn/bluies. The skin pigment around the eyes is flesh colored as well as a red or brown colored nose.
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