Genetic testing
What types of gene variations the normal person own?
Nucleic acid sequence
Sickle cell trait Cream gene Mannose receptor Responsibility assignment matrix Seal brown (horse)
Sickle_cell_trait-Haemoglobin_genetics Cream_gene-Analogous_conditions_in_other_animals Mannose_receptor-Types Responsibility_assignment_matrix-Variations Seal_brown_(horse)-Tyrosinase-brown
Normally, a person inherits two copies of the gene that produces beta-globin, a protein needed to produce normal haemoglobin (hemoglobin A, genotype AA). A person with sickle cell trait inherits one normal gene and one abnormal gene encoding haemoglobin S (haemoglobin genotype AS). 
The MATP gene is highly conserved, especially among mammals. The human MATP gene is 82% identical to the mouse MATP gene, 79% identical to the rat MATP gene, 35% to the zebrafish version, and 30% identical to the fruitfly MATP gene. The 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 gene. Other human MATP polymorphisms result in normal pigment variations, specifically fair skin, light eyes, and light hair in Caucasian populations. A polymorphism on the mouse MATP gene is known to be the cause of the "underwhite" coat color phenotype. The phenotype was first identified in the 1960s, and since then has been mapped successfully. Affected individuals have a reduction in eye and coat pigmentation, and irregularly shaped melanosomes. 
Humans express two types of mannose receptors, each encoded by its own gene: 
There are also a number of variations to the meaning of RACI participation types: 
Tyrosinase-related protein 1 (TYRP1) is a protein involved in melanin synthesis, and is encoded by the "TYRP1" gene, also called the "brown" ("b") locus. In humans, mutations in the "TYRP1" gene account for variations in "normal" skin, hair and eye coloration, as well as types of clinical Albinism. Mutations in the "TYRP1" gene of other mammals result in various reddish-brown coat color phenotypes: Brown in mice, Chocolate in cats, Chocolate in dogs, and Dun in cattle. The phenotypes associated with "TYRP1" mutations are typically rufous or chocolate rather than the black-dominated coats of seal brown horses, and usually result in pinkish-brown skin and light eyes. This is not the case for seal brown horses, and the role of "TYRP1" in seal brown was ruled out after it was sequenced in 2001. 