Until recently it was believed that chimeras were normally only produced in the laboratory and usually involved chimeras made from different, but closely related, species. In many cats, these forms of mosaicism will never be noticed because they naturally have black somewhere in their coloration when the black is quite unexpected and defies logic then mosaicism is assumed. The pelt diagram, based on a number of photographs (therefore not 100% accurate), gives some idea of his mosaicism. He would have bred as either a black or a blue (grey) cat depending on which embryo's cells hade formed his testicular tissue. This cat had normal male behaviour and was "very fertile". The effects of the white spotting gene are discussed in Bicolour Cats.
Some parts of Panda's body also appear to display a higher degree of white than others. In addition to his odd colouration, Panda was born with a deformed tongue and could not suckle, so was hand-reared. The colony into which he was born was inbred with more then 70% of the cats carrying Mo's genes. His father was a solid blue cat (Mo) and his mother was Aya (tabby-and-white). Like Pretty Boy Floid, Panda (born 1978) was probably an XY/XY chimera (2 fused male embryos) as he had a mixture of dilute (grey) and non-dilute (black) in his coat. In Japan in the 1980s, there was an instance of a beautiful blue-black-white fertile male (Panda) documented by zoologist Jeremy Angel. Mosaics which differ from the usual patterns are also noticeable. Somatic mosaicism and chimerism aren't restricted to red or red-and-white cats it's just that we are more geared up to looking for elusive fertile tortoiseshell males and tend to overlook the fact that some apparently normal tortoiseshell females may be due to genetic abnormalities. Poldhu the fertile blue-cream-and-white male Cornish Rex from the 1950s may also have been an XY/XY chimera the main difference between Poldhu and Floid being that Poldhu had cream (dilute) instead of red (non-dilute). A good example of this is the now famous Maine Coon Solkatz Pretty Boy Floid who is a mix of red, blue and white - a colour combination impossible in a normal XY male. The physical appearance and the sexual behaviour of an XX/XY chimera depends on which structures contain which chromosomes. The three X chromosomes in the animal may contain an assortment of different colour genes (especially if the mother mated several times and the eggs were fertilized by different fathers). In an XX/XY chimera, X chromosome inactivation will occur. If an XY egg fuses with an XX egg (a male embryo fuses with a female embryo), it gives a XX/XY chimera containing some tissues/organs which are genetically female and other tissues which are genetically male. This can come about through investigation of an illness or through visual clues such as tortoiseshell coats in male cats. In mammals, chimeras are usually only identified when there is a mismatch between the chromosomal sex (XX or XY) and the genitalia. Female chimeras can be XX/XX (two fused female embryos) or XX/XY (where the XX embryo cells form the gonads, producing a cat that appears physically female). An XY/XY chimera would be fully fertile.įemale cats can also be chimeras, but they are generally only noticed if they have a "genetically impossible" mix of colours in the coat e.g.
#Dnd chimera skin#
In an XY/XY chimera if one X has the O gene and the other does not then some fur will be ginger and some black because different parts of the skin originate from different eggs! It could also be a mix of any other colours found in male cats e.g.
If the two fertilized eggs are both XY, this gives an XY/XY male chimera. Until comparatively recently it was believed that chimeras were usually only produced in the laboratory and were extremely rare in nature, but it appears that chimerism is relatively common in animals that bear multiple offspring.Ī chimera is the result of 2 fertilised eggs fusing to become a single kitten. Only a few tortie tomcats were XXY (Klinefelter) individuals, and these generally had unusual conformation as well as tortoiseshell or calico patterns. The second most common cause was somatic mutation (mutation in tissue cells). Karyotype testing of male tortoiseshell cats found that most common causes of tortoiseshell tomcats was mosaicism, or chimerism, being XX/XY in all or some tissues. Because sex-linked orange and the X-inactivation process were well-known, tortoiseshell male cats were suspected to have chromosomal abnormalities, particularly in the sex chromosomes. Manticore types.By the end of the 20th century, karyotype (chromosome) and genetic testing had become common methods to determine if a cat with ambiguous genitalia or fertility issues had a chromosomal abnormality.