effect on red pigment has not yet been explained. The champagne dilution affects both black and red pigments equally, the silver dapple gene affects only black pigment, and pearl exhibits a recessive mode of inheritance and only affects red pigment. Unlike the cream gene, pearl does not seem to affect the mane and tail to a greater extent than the body coat, a feature of cream that is most vividly illustrated in the palomino coat color. This characteristic of the cream gene is also unexplained. The disparity in effects on red and black pigments is easy to identify in buckskins, with their black points, but it is also visible in CCr/CCr homozygotes: perlinos (homozygous cream on a bay coat) often retain points that are a darker shade of cream. This unusual feature enables what are called cryptic creams. A certain percentage of dark bay, seal brown, and black horses exhibit such subtle dilution of their coats as to be misregistered. In the study that mapped the cream gene, three horses registered as seal brown, dark bay or bay were actually smoky black and buckskin. This is one way by which the cream gene is transmitted through generations without being identified. Horses born palomino, buckskin, and smoky black, but also carry the gray gene, have a hair coat that turns white as they age and are usually registered as "gray" rather than as their birth color. This is particularly a common occurrence in the Connemara breed. Horses sold after turning fully gray may surprise breeders by producing golden or cream offspring. This effect - stronger expression on red pigment - is also seen in coat pattern genes in horses. In general, white markings are more pervasive in chestnuts than in non-chestnuts, to the extent that homozygous non-chestnuts (which carry the "Extension" (E) gene and may also carry the Agouti gene) were more modestly marked than non-chestnuts heterozygous for the E allele. This effect has also been identified and studied in the Leopard complex patterns. Analogous conditions in other animals The SLC45A2 gene is best known in humans as being the location of a mutation that results in human type IV oculocutaneous albinism (OCA4). Type IV oculocutaneous albinism, like other types of human albinism, results in hypopigmentation of the skin and eyes, with increased rates of skin cancer and reduced visual acuity. None of these effects are associated with the equine cream