Recessive Genes

There are several "base morphs" in Kenyan Sand Boas. Base morphs are mutations that have been found to exist in the species and have proven to be genetically inheritable. One of the most common morphs found throughout the reptile community is albinism. Albinism is a mutation that causes a lack of  melanin production and thus, reduced pigmentation. The melanin gives the snakes the normal orange and black coloration, and without it it, the snakes saddles become a yellow/pink sort of color but keep the vibrant orange. This gene is what is called recessive. A recessive gene is a gene that can be overshadowed by a dominant gene visually, but keeps the genetic potential. The visual appearance is what is called the phenotype and the genetic makeup is called the genotype. A snake that looks normal has a normal phenotype, and a snake that looks albino has an albino phenotype. Normal is dominant, while as previously stated, albino is recessive. This means that if a normal sand boa were bred to an albino, you could not visually see the albino in the babies. This is because the normal gene overshadows the albino gene. The genotype however is not normal. It would be considered heterozygous. If a normal snake is homozygous normal, it would mean that it was purely normal or "NN." This means that it would carry no recessive genes. Basically what you see is what you get. Heterozygous animals appear to be normal but they carry a gene not expressed in the phenotype. "Na" for example. Now for the albino gene to be expressed, the snake would have to be homozygous albino, or "aa". The reason being that there is no dominant gene to overshadow it. However, you could produce an albino phenotype by breeding two normal phenotypes. The way this is done is by breeding two snakes that carry the albino gene, aka heterozygous genotype with a normal genotype. This would be represented by Na x Na which could produces normal or albino phenotypes. So if you see a snake advertised as Normal het Albino, that means that the animal has a normal phenotype but is heterozygous and carries the albino gene, but because it is recessive, it cannot be visually observed. ALL albinos are homozygously albino, because if it carried the normal gene, it wouldn't allow for the albino phenotype to be expressed.