Cats
Amber also occurs with silver and in bicolours/tabbies -and-white.)
The provisionally named Russet Burmese is an experimental Burmese colour in New
Zealand. In 2007, Nicki and Bob Mackenzie's line of seal (brown) Burmese (carrying dilute
and chocolate) produced "odd-coloured lilac" kittens which gradually lightened as they grew,
progressing through chocolate ticked tabby to red. The kittens traced to the same father and
two related females (mother and daughter) and all three shared a common ancestress only a
few generations back. DNA testing showed the russet kittens to have the standard seal or
standard chocolate genes, meaning there is an a different gene causing the colour change.
Russet kittens also tended to be larger than their littermates, both at birth and as adults.
Russet appears to be a recessive gene from a spontaneous mutation. It causes the black
pigment (eumelanin) to gradually fade to almost nothing while leaving the red pigment
(phaeomelanin) unaffected
annaabi.ee 
