TheTaqpep gene
The genetic test for tabby allows a distinction between the mackerel tabby coat pattern and the blotched or classic tabby coat pattern. Mackerel tabby is characterized by vertical stripes with regular spacing, blotched tabbies by a less organized dark pattern over a light background.
Variants in the Teqpep gene (Transmembrane aminopeptidase Q) are responsible for the arrangement of the color patterns. Both Mackerel and Blotched patterns are only expressed in tabby cats in which the A-Locus (agouti) is either A/A or A/a. If the A-Locus is a/a, Tabby Mackerel or Tabby Blotched won't be expressed.
Mackerel
The Ta
M variant is responsible for the Mackerel pattern in tabby cats.
Mackerel cats would have TaM/TaM or TaM/Tab at the T-Locus.
Blotched
While, the Ta
M variant is responsible for the Mackerel pater, the Ta
bis repsonsible for the Blotched pattern in tabby cats. The Ta
b variant causes the ancestral pattern of dark narrow stripes (Ta
M/-, Mackerel) to expand into less well-organized large whorls (Ta
b/Ta
b, Blotched)
Blotched cats would have Tab/Tab at the T-Locus.
Order of Dominance
TaM > Tab
Mackerel Ta
M is dominant to Blotched Ta
b, and so Mackerel can be either Ta
M/Ta
M or Ta
M/Ta
b . Mackerel can carry the Blotched.
Blotched cats would have Tab/Tab at the T-Locus
