A tabby is a cat with a distinctive coat that features stripes, dots, or swirling patterns. Tabbies are often mistakenly assumed to be a breed of cat. In fact, the tabby pattern is a naturally occurring feature that may be the original coloration of the domestic cat's distant ancestors. Tabby coloration is found in many breeds of cat, as well as among the general 'moggy' (mixed-breed or mongrel) population. When cats are allowed to breed randomly, the coloration of the population tends toward brown mackerel tabbies with green eyes, much like humans with brown hair and green eyes, of which leading geneticists to believe that this is the common wild phenotype of the domestic cat. The tabby usually has an " M " mark on the forehead.
The word comes from French tabis, which was earlier atabis, and in medieval Latin attabi. The initial origin of the word seems to be from the Attabiyah section of Baghdad where a type of striped silk was made that was later used to describe cats.
The mackerel tabby pattern has vertical, gently curving stripes on the side of the body. The stripes are thin and may be continuous or broken into bars and spots on the flanks and stomach. Often, an 'M' shape appears on the forehead. Mackerels also feature a 'peppered' nose, where black spots appear along the pink tip of the nose. Mackerels are also called 'fishbone tabbies'. Mackerel is the most common tabby pattern.
Classic (or 'blotched') tabbies have a similar 'M' pattern on the head, but the body markings are very different, having a whorled and swirled pattern with thicker stripes that make what are referred to as "butterfly" patterns on their shoulders and usually a bulls-eye or oyster pattern on the flank. The legs and tail are more heavily barred and the pattern is variable with respect to the width of the bands.
The ticked tabby pattern produces hairs with distinct bands of color on them, breaking up the tabby patterning into a salt-and-pepper appearance. However, ghost striping or "barring" can often be seen on the legs, face and belly.
The spotted tabby may not be a true pattern, but a modifier that breaks up the mackerel pattern so that the stripes appear as spots; the stripes of the classic pattern may be broken into larger spots. Both large spot and small spot patterns can be seen in the Australian Mist, Bengal, Egyptian Mau, and Ocicat breeds.
Many tabbies have a distinct 'M' marking on their forehead. There are several legends about where this came from. One relates that the Virgin Mary bestowed an M on a tabby's head after it helped keep the baby Jesus warm. In reality, the historical Mary would have spoken Aramaic and the first letter of her name is the Hebrew letter Mem (מ).
The Tabby is a coat pattern and not a color. It can show up in combination with a variety of coat colors. A cat's coat can be described as red tabby or gray tabby. Black and blue are colors that usually show up without tabby markings, but with some cats, a faint tabby pattern can actually be noticed. White is the only color that never has any tabby markings.
Bi-colors can have the tabby pattern show up on the colored patches of their coat. Tortoiseshell cats sometimes display a pattern where the three-colored tortoiseshell pattern is mixed with tabby markings. These cats are known as "torbies".
The most commonly identified breed of Tabby - the Classic Tabby - by the public tends to have a blotched pattern of dark browns, ochres, and black. With this breed uniform or nigh on uniform striping around the circumference of the tail defines feral origins in that particular cat's family tree.
In cat genetics, pattern is unrelated to color, and so the tabby pattern may occur in any cat color, including tortoiseshell (tortoiseshell tabby cats are often called 'torbies'). White spotting of any level can also appear in combination with tabby patterns.
The agouti gene, A/a, controls whether or not the tabby pattern is expressed. The dominant A reveals the underlying tabby pattern, while the recessive non-agouti or "hypermelanistic" allele, a, prevents it. Solid-color (black or blue) cats have the aa combination, hiding the tabby pattern, although sometimes a suggestion of the underlying pattern can be seen (called "ghost striping"). However, the O gene for orange color suppresses the aa genotype, so there is no such thing as a solid orange cat.
The primary tabby pattern gene, Mc/mc, sets the basic pattern of stripes that underlies the coat. Mc is the wild-type tabby gene and produces what is called a 'mackerel striped' tabby. 'Classic' tabbies are cats who also possess mc, a recessive mutant gene that produces the blotched pattern.
The ticked pattern is on a different gene locus than the mackerel and classic tabby patterns and is epistatic to the other patterns. A dominant mutation, Ta / ta, masks any other tabby pattern, producing a non-patterned or 'agouti' tabby with virtually no stripes or bars. If the ticked pattern gene is present, any other tabby pattern is masked. Cats homozygous for the ticked allele (Ta / Ta) have less barring than cats heterozygous for the ticked allele.