Maine Coon — Color Genetics & EMS Calculator

Common recessive carriers

Approximately 15–20% of tabby-pattern MCOs carry a hidden non-agouti (a) allele at the A locus, producing solid offspring when paired with another carrier. Dilution (d) is widely distributed in the population; matings between two heterozygous (Dd) cats statistically produce 25% dilute offspring. Chocolate (b) and lilac (b + d) are valid within the MCO standard and occur as rare recessives.

Breed-specific restrictions

Maine Coons cannot carry the colourpoint allele (cs) — pointed MCOs are not recognized under FIFe or TICA standards and any cs expression constitutes a disqualifying fault. The Amber (e/e at the Extension locus) allele, while documented in Norwegian Forest Cats, is not accepted in the MCO standard. White (W locus) dominant white is permitted, but must be differentiated from high-grade bicolor (Van, 01) in EMS registration.

Pattern quirks

Classic blotched tabby (22) and mackerel tabby (23) are the dominant pattern expressions. Spotted tabby (24) is accepted and occurs naturally. Ticked tabby (25) is considered atypical and is not universally accepted across all registries; FIFe does not list it as standard for MCO. The Inhibitor (I) locus produces silver/smoke variants across all base colors and pattern combinations.