By Jorge
This blog explains other cats that don't have a fixed home but they are adopted by the neighborhood, stray cats but they are being fed by the humans in the area where these cats live. Even a couple of memes of cats are present in Saving the Michi AR!
Many of the cats here are tabby mackerel cats, orange, blacks, tuxedo, etc. You name it, most probably it will be there.
Watching all these cats and their different colors, made me question: what gives cats their colors in their coats? We will describe a little bit why this happens.
Cat coat colors and patterns are determined by complex genetic interactions involving multiple genes that control pigment production, distribution, and density. Here's a breakdown of the key genetic mechanisms:
Core Pigments: The Building Blocks
Eumelanin: Produces black/brown pigment.
Pheomelanin: Produces red/orange/yellow pigment.
All cat colors come from different expressions, dilutions, and mixtures of these two pigments.
Genes that Control Color
Several key genes influence coat color:
-
B gene (Black): determines whether eumelanin is black, chocolate, or cinnamon.
-
D gene (Dilution): dilutes black -> gray (blue), chocolate -> lilac, cinnamon -> fawn, orange -> cream.
-
O gene (Orange): converts eumelanin into pheomelanin, making cats orange or tortoiseshell.
-
A gene (Agouti): controls whether hairs are banded (tabby) or solid.
-
W gene (White): masks all pigment (solid white cats).
-
S gene (Spotting): creates white patches (bicolor, tuxedo, etc.).
Coat Patterns
-
Tabby: striped, spotted, or swirled (from agouti gene expression)
-
Solid: full color, no visible pattern
-
Tortoiseshell & Calico: mix of black and orange due to the X chromosome (why they’re almost always female)
-
Pointed (Siamese, Himalayan): cooler body parts (ears, tail, paws, face) show darker pigment due to a temperature-sensitive gene
Other Factors
-
Length & texture of fur: changes how the color looks (long fur makes colors appear lighter or “smoky”)
-
Age: kittens may be born lighter/darker and change as they grow
-
Sunlight: dark cats can “rust” into brownish shades if exposed to sun often
Key Genes Controlling Coat Color
A. Color Basics
|
Gene |
Function |
Variants |
|
B (Black) |
Controls eumelanin darkness |
B (black) > b (chocolate) > b' (cinnamon) |
|
O (Orange) |
Switches eumelanin → pheomelanin |
O (orange) > o (non-orange) |
|
D (Dilution) |
Lightens pigments |
D (full color) > d (dilute) |
Example:
B + O + D = Vibrant orange
B + o + d = Gray ("blue")
B. White Patterns
|
Gene |
Role |
Outcome |
Gene |
|
Agouti (A) |
Controls banding on hairs |
A (tabby) > a (solid) |
Agouti (A) |
|
Tabby Modifiers |
Refines pattern |
Mackerel (stripes), Classic (swirls), Ticked |
Tabby Modifiers |
|
Inhibitor (I) |
Blocks pigment at hair base |
Smoke or silver coats |
Inhibitor (I) |
Sex-Linked Traits
Orange gene (O) is X-linked:
Males (XY): Only need one O gene to be orange.
Females (XX): Need two O genes: 80% of orange cats are male.
Tortoiseshell/Calico:
Requires two X chromosomes + mix of O/o genes: Almost always female (rare males are XXY).
Real-World Examples
|
Cat |
Genotype |
Appearance |
|
Black Cat |
aa + B_ + dd |
Solid gray ("blue") |
|
Orange Tabby |
AA + O + D |
Bright stripes |
|
Tortoiseshell |
X^O X^o + aa |
Black/orange patches |
|
White Cat |
WW or W_ |
Pure white (may have deafness risk) |
|
Siamese |
c^s c^s (temperature-sensitive albino) |
Dark points + pale body |
Key Takeaways
All colors derive from eumelanin (black/brown) and pheomelanin (red/yellow)
Dilution genes create variations (gray, cream)
White masking and spotting genes override base colors
Tabby patterns require the agouti gene
Sex chromosomes control orange/calico/tortie patterns
In short: a cat’s coat color is the result of pigments (black vs. red), genes (that dilute, block, or mix them), and patterns (tabby, solid, patched, pointed).
In Saving the Michi AR, there are in total 12 pictures of feral michis that were found in the wild. Can you find them all?
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