Эссекс — это маркировка такая
С сайта afrma.org:
ESSEX–To be recognized in any standard color, remembering that the effect of the gene responsible is to lighten the top color. The darkest area is along the spine, becoming less intense down the sides of the animal. The gradual fading of color continues onto the belly which is off white, with no spotting of darker color. When viewed from above, the fading effect should be symmetrical, having no clear demarcation. The fading effect also to be seen on the legs so that the feet are also off white. There should be no obvious patches of contrasting color. Pied tails not to be penalized. A head spot is essential; this must be well defined, centrally placed on the forehead and symmetrical. Genetics: Unproven lethal dominant gene on H locus tentatively named Hro * (N.F.R.S.; accepted 4-30-05)
http://www.afrma.org/ratmkd.htmВ России таких, вроде бы, пока нет.
