Cat Genetics Guide: Coat Patterns and Mating Basics
This article is part of an ongoing series exploring cat genetics. Understanding the fundamentals of DNA, genes, inheritance, and coat colour is essential to fully grasp the concepts here. If you haven’t read parts one to four, we recommend starting there before continuing.
Cats display a remarkable variety of coat patterns, ranging from simple solid colours to complex tabby and pointed markings. This guide provides a basic overview of the most common patterns breeders encounter, focusing on how these traits inherit genetically. While many coat patterns involve interactions of multiple genes and polygenes, this article introduces the essentials to help breeders predict outcomes responsibly and ethically.
Colourpoint, Sepia, and Mink Patterns
These distinct patterns are most often seen in pedigree cats such as Siamese or related breeds, though occasionally non-pedigree cats may produce pointed offspring. The three patterns result from different mutations at the same gene locus known as the C gene.
The dominant normal C gene produces solid-coloured cats. Recessive mutations include colourpoint (Cs) and sepia (cb). A cat with two copies of the colourpoint gene will show darker extremities—ears, paws, tail—and a lighter body coat. Sepia cats have a darker body coat overall with only subtly darker points. When a cat carries one copy of each (Cs and cb), the resulting coat has an intermediate appearance between colourpoint and sepia.
These patterns are temperature-sensitive: cooler body areas express more pigment and appear darker, a mechanism that beautifully shapes the distinctive pointed look.
Tabby Patterns Explained
The tabby pattern is intricately controlled by several genes, with the first being the dominant Agouti gene. This gene enables alternating bands of pigment along each hair shaft, creating the classic striped or spotted effects.
Cats with two copies of dominant agouti will have tabby markings in all offspring, regardless of the mate’s pattern. Cats with only one copy may produce some non-tabby kittens. Cats lacking dominant agouti will not show tabby patterning themselves but can produce tabby offspring if mated with a tabby.
Further genes determine the specific tabby design: mackerel tabby (Mc) features narrow stripes, while classic tabby displays swirls. Other patterns like ticked tabby and spotted are influenced by yet more genetic factors. Research continues into how these genes interact, but it’s clear that multiple genes and modifiers combine to create the wide array of tabby appearances seen across breeds.
Solid Coat Colours and Dilution
A solid coat describes a uniform colour without pattern. Black is the most common, requiring only one dominant gene copy, making it prevalent among cats. Red colouring is sex-linked and less dominant, influencing breeding outcomes distinctly by sex.
Rarer colours like chocolate, cinnamon, blue, cream, and fawn involve recessive alleles or dilution genes that affect pigment intensity and expression. For example, blue and cream colours require dilution genes, with cream being a dilute of red. These layers of genetic control influence the rarity and appearance of solid coat colours in pedigrees.
Predicting Outcomes in Cat Matings
Successful and ethical breeding requires an understanding of which recessive genes each parent carries to predict kitten coat colours and patterns accurately. Breeders “deconstruct” known phenotypes into potential genotypes by removing recognised pattern influences, then “construct” the desired phenotype by adding specific genes expected to be present or carried.
For example, deconstructing a blue tortie tabby colourpoint might involve peeling back the colourpoint effect to reveal a blue tortie tabby, then further removing tabby and dilution genes to identify the base colours. Conversely, constructing a lilac tortie sepia starts with a tortie, adds chocolate, then dilute, followed by two copies of the cb gene.
Applying Genetics to Predict Kitten Colours
By combining constructed genotypes, breeders can anticipate likely kitten coat colours and patterns. Using the example of a blue tortie tabby carrying colourpoint and dilute mated with a chocolate colourpoint carrying dilute, predicted kittens might include tabby and non-tabby, colourpoint and non-colourpoint, and various colour dilutions depending on allele combinations inherited.
Male kittens might be black, blue, red, or cream, with tabby and/or colourpoint patterns. Female kittens can also present tortie variations, with red being sex-linked requiring careful consideration of parental genetics.
Responsible Breeding Recommendations
Cat breeding is a scientific enterprise requiring careful genetic knowledge. Every breed has unique genetic quirks needing deeper study beyond general patterns. Always prioritise health and welfare by working with reputable breeders and pursuing genetic testing when available.
Understanding genetics helps ensure healthier litters and supports the preservation of breed standards while reducing inherited health problems. Responsible breeders aim for patterns and colours that enhance breed quality without compromising cat wellbeing.
Further Reading: Cat Genetics Series
