Cómo se hereda el color en gatitos: genética felina
Genetics is the key to understanding coat colour in cats. In this fourth part of our series, we explore how different colours arise from a few core genes, using a straightforward approach accessible even to those new to genetics.
The Building Blocks of Cat Coat Colour
Cat coat colour is determined by two key pigments: eumelanin (which creates black tones) and phaeomelanin (which creates red/orange tones). These pigments are then modified by various genes that affect how they appear on the cat’s fur. The sex of the cat also plays a role, particularly for red colouration, as the gene responsible is located on the X chromosome.
Black Cats and Dilution
A cat with two copies of the non-agouti gene (aa) and producing only eumelanin appears black, unless modified. The dilution gene can change this black to blue (grey), creating blue cats. Cats that are heterozygous (one black and one dilution gene) appear black because black is dominant over blue.
Brown and Chocolate Variations
A separate gene controls whether eumelanin appears as black or chocolate (brown). A cat with two copies of the chocolate gene appears chocolate, while one copy may not be visually apparent (it depends on dominance). The same dilution gene that turns black to blue turns chocolate to lilac, and cinnamon to fawn.
Red (Orange) and Cream Cats
Red coat colour comes from a gene on the X chromosome. This means male cats (XY) only need one copy to be red, while female cats (XX) need two copies. A female with one copy may show a mix of red and black, resulting in a tortoiseshell pattern. A diluted red appears as cream. This genetic mechanism explains why tortoiseshell and calico cats are almost always female, and why red cats are more commonly male.
The White Gene and Its Variations
The dominant white gene masks all other colours, producing a completely white cat. However, this is different from other white patterns, such as the tuxedo (bi-colour) or the pointed patterns of Ragdolls and Snowshoe cats. These variations are controlled by different genes and have their own inheritance patterns. White cats with blue eyes can be prone to deafness, which is linked to the dominant white gene.
Why Does This Matter?
Understanding cat coat colour genetics helps breeders predict the likely outcomes of matings, maintain breed standards, and avoid some hereditary problems. For example, knowing that white cats with blue eyes may be deaf due to gene linkage helps breeders make more informed pairings. For cat owners, knowing how colours are inherited can explain why some kittens in a litter look different from their parents or siblings.
Coat colour in cats is a fascinating area of genetics that reflects the interplay of multiple genes, sex linkage, and dominance. As our understanding deepens, it becomes a useful tool in responsible cat breeding and the promotion of feline health and wellbeing.
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