Why Some Kittens Are Born with Tabby Markings

The Ubiquitous Tabby Gene

The tabby pattern isn’t a specific color, but rather a pattern that overlays the cat’s actual color. Every cat possesses the agouti gene, which plays a crucial role in determining whether a cat will display tabby markings. When the agouti gene is expressed, it allows for the production of a protein that switches the production of pigment from black (eumelanin) to reddish-brown (pheomelanin). This creates the characteristic banded hairs seen in tabby cats.

However, the agouti gene’s influence depends on other genes. If a cat has a non-agouti gene, it will be solid colored, masking any underlying tabby pattern. Therefore, the presence of the agouti gene is the primary reason why some kittens are born with tabby markings.

It’s important to note that even seemingly solid-colored cats may carry the tabby gene. This can sometimes be subtly revealed in certain lighting conditions, a phenomenon known as “ghost striping”.

Types of Tabby Patterns

While the agouti gene enables tabby markings, other genes determine the specific type of tabby pattern that appears. There are four primary tabby patterns:

• Classic Tabby: Characterized by bold, swirling patterns on the sides of the body. Often features a “bullseye” pattern on each side.
• Mackerel Tabby: Features narrow, parallel stripes running down the sides of the body, resembling a fish skeleton. This is the most common tabby pattern.
• Spotted Tabby: Displays spots of varying sizes and shapes across the body. These spots are essentially broken mackerel stripes.
• Ticked Tabby: Also known as Abyssinian tabby, this pattern lacks distinct stripes or spots on the body. Instead, each hair is banded with alternating light and dark colors, creating an overall agouti appearance.

These distinct patterns are caused by variations in the Tabby (Ta) gene. The Ta gene has different alleles that determine whether a cat will have a classic, mackerel, or ticked tabby pattern. Spotted tabbies are believed to be a variation of the mackerel tabby pattern, modified by a separate gene.

The interaction of these genes is what creates the wide variety of tabby patterns seen in cats. Understanding these genetic interactions helps explain why some kittens are born with specific tabby markings.

The Role of the Agouti Gene in Detail

The agouti gene (A) has two main alleles: A and a. The A allele is dominant and allows for the expression of tabby patterns. The ‘a’ allele is recessive and suppresses the tabby pattern, resulting in a solid-colored cat. A kitten must inherit at least one copy of the A allele to display tabby markings.

Therefore, a kitten with a genotype of AA or Aa will be a tabby, while a kitten with a genotype of aa will be solid-colored. This simple genetic principle explains why some kittens inherit tabby markings while others do not.

The agouti protein, produced by the A allele, regulates the production of melanin in the hair follicles. It essentially tells the pigment-producing cells to switch between producing eumelanin (black/brown pigment) and pheomelanin (red/yellow pigment), creating the banded appearance of tabby hairs.

Sex-Linked Orange Gene and Tabby Markings

The orange gene (O) is located on the X chromosome and influences the production of pheomelanin (orange pigment). This gene interacts with the agouti and tabby genes to create unique color and pattern combinations. Because females have two X chromosomes (XX) and males have one X and one Y chromosome (XY), the orange gene’s expression differs between the sexes.

If a female cat inherits two copies of the orange gene (OO), she will be orange or tortoiseshell (a mix of orange and black). If she inherits two copies of the non-orange gene (oo), she will be black or another non-orange color. If she inherits one of each (Oo), she will be tortoiseshell.

Male cats, with only one X chromosome, will be either orange (if they inherit the O allele) or non-orange (if they inherit the o allele). When combined with the tabby gene, the orange gene can create orange tabby patterns, also known as marmalade cats.

Genetic Combinations and Tabby Variations

The combination of the agouti gene, the tabby gene, and the orange gene (in some cases) creates a vast array of tabby variations. For example, a cat with the genotype A/A, T/T (for mackerel tabby), and o/o will be a black mackerel tabby. A cat with the genotype A/a, Ta/Ta (for classic tabby), and O/o will be a tortoiseshell classic tabby.

Other genes, such as those that control dilution (making colors lighter) and spotting (creating white patches), can further modify the tabby pattern. These complex genetic interactions are responsible for the incredible diversity of cat coat colors and patterns.

Understanding these genetic combinations allows breeders to predict the coat colors and patterns of kittens. However, genetics can be unpredictable, and surprises can always occur!

Environmental Factors

While genetics play the primary role in determining tabby markings, environmental factors during development can also have a subtle influence. These factors are not fully understood, but they are believed to affect the expression of genes involved in pigmentation.

For example, temperature during gestation may influence the intensity of coat color. Nutrition and overall health of the mother cat can also impact the development of the kittens’ coat.

However, the influence of environmental factors is generally minor compared to the strong genetic control over tabby patterns.

The Evolutionary Significance of Tabby Markings

The prevalence of tabby markings in domestic cats suggests that these patterns may have some evolutionary significance. One theory is that tabby patterns provide camouflage, helping cats blend in with their surroundings and stalk prey more effectively. This camouflage would have been particularly important for wild ancestors of domestic cats.

Another theory is that tabby markings serve as a form of visual communication, allowing cats to recognize each other and establish social hierarchies. The distinct patterns may also help cats avoid aggression by signaling their individual identity.

Regardless of the specific evolutionary advantage, the widespread presence of tabby markings indicates that these patterns have been beneficial for cats throughout their evolutionary history.

Tabby Markings in Different Cat Breeds

Tabby markings are found in many different cat breeds, both purebred and mixed-breed. Some breeds, such as the American Shorthair and the Maine Coon, are particularly known for their striking tabby patterns. Other breeds, such as the Abyssinian, exclusively display the ticked tabby pattern.

The specific tabby patterns that are allowed or preferred in a breed standard vary depending on the breed. Some breeds may have specific color restrictions as well. For example, the Bengal breed is known for its spotted tabby pattern, which resembles the coat of a wild leopard.

The presence of tabby markings in a breed is determined by the genes that are present in the breed’s gene pool. Breeders can select for specific tabby patterns and colors to create cats that meet the breed standard.

Conclusion

The presence of tabby markings in kittens is a result of complex genetic interactions. The agouti gene is essential for expressing the tabby pattern, while the tabby gene determines the specific type of tabby pattern. Other genes, such as the orange gene and genes that control dilution and spotting, can further modify the tabby pattern.

While genetics play the primary role, environmental factors may also have a subtle influence. The prevalence of tabby markings suggests that these patterns may have some evolutionary significance, such as providing camouflage or facilitating visual communication.

Understanding the genetics behind tabby markings allows us to appreciate the incredible diversity of cat coat colors and patterns. So, the next time you see a kitten with striking stripes or spots, remember the fascinating genetic story behind its beautiful coat.

FAQ

Why are some kittens born with tabby markings and others are not?

Kittens are born with tabby markings if they inherit at least one copy of the dominant agouti gene (A). This gene allows for the expression of tabby patterns. Kittens that inherit two copies of the recessive non-agouti gene (aa) will be solid-colored.

What are the different types of tabby patterns?

The four main types of tabby patterns are classic, mackerel, spotted, and ticked. Classic tabbies have swirling patterns, mackerel tabbies have narrow stripes, spotted tabbies have spots, and ticked tabbies have banded hairs without distinct stripes or spots.

Does the orange gene affect tabby markings?

Yes, the orange gene (O) can affect tabby markings. If a cat inherits the orange gene and also has the tabby gene, it will display an orange tabby pattern, also known as a marmalade cat. The orange gene is sex-linked, so its expression differs between male and female cats.

Can environmental factors influence tabby markings?

While genetics play the primary role, environmental factors during development can have a subtle influence on tabby markings. Temperature, nutrition, and the overall health of the mother cat may affect the expression of genes involved in pigmentation.

Are tabby markings found in all cat breeds?

Tabby markings are found in many cat breeds, both purebred and mixed-breed. Some breeds are particularly known for their striking tabby patterns, while others may only display specific types of tabby patterns.

What is the most common type of tabby marking?

The most common type of tabby marking is the mackerel tabby, characterized by narrow, parallel stripes running down the sides of the body.

Do tabby cats have a specific personality?

No, tabby markings do not directly correlate with a specific personality. A cat’s personality is influenced by a combination of genetics, environment, and individual experiences.

Can a cat be both tabby and solid-colored?

No, a cat cannot be both tabby and completely solid-colored. If a cat has the agouti gene, it will display some form of tabby markings, even if they are faint or subtle. Cats that appear solid-colored have the non-agouti gene, which suppresses the tabby pattern.

Is the ticked tabby pattern considered a true tabby pattern?

Yes, the ticked tabby pattern is considered a true tabby pattern. Although it lacks distinct stripes or spots on the body, the banded hairs create an overall agouti appearance, which is characteristic of tabby cats.

How do breeders influence tabby markings in cats?

Breeders can influence tabby markings by selecting for specific genes that control tabby patterns and colors. By carefully choosing which cats to breed, they can increase the likelihood of producing kittens with desired tabby markings.