Burmese nature is known to be unique just like their genetic make-up.
All dominant genes have an upper case letter and all recessive genes a lower case letter. Recessive factors of inheritance can only show up in homozygous form.
A homozygous sable Burmese has following genotype:
aa cbcb BB DD ii
We would like to introduce the relevant Burmese genes as follows :
a = non agouti
A = agouti
is a pattern of pigmentation in which individual hairs have serveral
bands of light and dark pigment.
cb = Burmese gene
The gene C (colour), dominant over all others is mutated into cb. This Burmese gene creates a brownish coat for a genetically black cat (sable burmese). The Burmese gene is a variation of the albino serial. The typical Burmese appearance can be traced back to the homozygous recessive gene cb.
= gene for the colour black
b = dark brown allele (chocolate), a mutation of the allele B, reduces black to a brown, chocolate colour.
D = dense gene - allele for non-dilution, is responsible for full pigmentation and is a dominant gene.
= the mutation of the dense gene D is d
(dilution) and modulates the intensity of the coat colour to a more
pale coat. In recessive form the dense gene (dd) is
known as the dilution gene as it dilutes
black (sable) and chocolate to blue and lilac respectively.
There are four different kinds of solid colours.
Once again: the genes of a homozygous sable Burmese
aa cbcb BB DD ii
2) blue = dilution of black is blue
chocolate = next to black there is
brown. This is the mutated allele to black B and changes
the black pigmentation into different shades of chocolate, shown by
the symbol b.
lilac = the chocolate - brown gene is diluted to bb
blue / lilac / brown
Foto © copyright by: Birgit Dietzel, Apsaras Burmakatzen
Foto © copyright by: A. Wilde, Burmesen of Royal Lion
We have four kinds of sables :
BB DD = sable ( genetically black )
BB Dd = sable, carrying blue
Bb DD = sable, carrying chocolate
Bb Dd = sable , carrying chocolate and blue
BB dd = blue
dd = blue , carrying chocolate
We have two kinds of chocolate :
bb DD = chocolate
bb Dd = chocolate, carrying blue
bb dd = lilac burmese, they do not have any dominant genes
Red , Cream , Tortoiseshell
Responsible for these colours is the gene for Orange.
An interesting characteristic of the orange gene is that it is carried on the X- chromosome, which makes it sex-linked.
The orange gene has two alleles: non - orange o and orange O.
The non - orange allel o is recessive and allows full expression of the black locus. The dominant orange allele O, however, influences expression of the black and agouti loci because it substitutes the production of phaeomelanin for eumelanin. It makes the effect of the black gene by converting a black or brown coat to orange.
In male cats this locus can produce only two phenotypes : black or orange. If a male carries the orange allele, he will be orange (red/ cream).
In females it can produce three phenotypes: black (oo), orange (OO) and tortoiseshell (Oo).
Females are XX meaning they have two X -chromosomes. If both chromosomes carry the orange allele then the coat will be orange (OO) - red/cream -. If she is heterozygous (Oo) her coat will be a patchwork of orange and black patches, called tortoiseshell.
OO DD = orange, homozygous red
Oo DD = tortoiseshell - seal-tortie and chocolate-tortie
OO dd = cream
Oo dd = tortoiseshell - blue-tortie and lilac-tortie
The gene for orange overlaps all possible colour varieties.
All these 10 colours are recognized in cat organizations worldwide.
The Burmese come without any barring and in warm colours which are generated through selective breeding.
The rufousing gene:
Nowadays Burmese appear without barring and come in warm colours due
to selective breeding
are efforts (as in other breeds too) to introduce the silver and agouti
gene into the Burmese breed. New colours such as silver, ticked, smoke
as well as caramel, apricot, fawn and cinnamon were established.
Text © copyright by: Silvia Röll-Becker, Burmakatzen vom Silvan
Translation © copyright by: Irmgard Thormann, Mackintosh Burmese Cats
Foto © copyright by: Bettina Koch, Burmakatzen von Merapi