What Are Heterozygous Boas?

Stating that an organism is heterozygous (het-er-a-zye-gus) describes a genetic condition in which the organism carries two different sets of genetic alleles (a type of gene.) However, the organism only displays one outward trait. As far as boas are concerned, the case is the same. Heterozygous boas carry two different alleles, usually ones which determine the snake's coloring, even if they only display one genetic trait.

  1. Types of Heterozygous Traits

    • When a boa is described as being a heterozygous or a "het" snake, it means it has a coloring abnormality in its genetic line. Many of these abnormalities are highly sought-after, however, and breeders want to know what type of abnormality exists in the genetic line. Traits such as amelanism (albinism), anerythristim and hypomelanism produce rare and attractive colors or patterns on snakes. Heterozygous snakes may carry one or more of these recessive (or, in the case of hypomelanism, co-dominant) genes while still looking ordinary. Breeders are able to pair such a trait with another snake who carries the same recessive gene to produce a boa that appears completely different.

    Albinism in Boas

    • Albinism denotes a lack of melanin in a boa, and snakes that carry this gene may have albino babies if they breed with another snake that carries the same gene. These boas have no black scales, making their red coloring seem more vibrant. Merely carrying the gene is not enough to pass it on to future generations, though, because the gene is recessive. However, an albino boa's litter will carry the gene, even if the babies look ordinary.

    Anerythrisic Boas

    • Anerythrisic boas are genetically opposite to albino boas. This is because anerythrisim denotes a lack of erythrin, the pigment that allows for red and orange coloring in boas. They are occasionally referred to as "black boas." Anerythrism is a recessive condition and snakes carrying this gene are sought to create genetic combinations. Babies born from such a litter will carry the phenotype able to produce anery boas, but the characteristic may or may not manifest itself.

    Hypomelanism in Boas

    • Hypomelanism is a genetic condition in boas that blocks the manifestation of black pigment and displays a brighter array of oranges and browns. It is also thought of as partial albinism, as there is a partial lack of pigment. As this is a co-dominant gene, hypomelanistic offspring from this sort of boa are just as likely as ordinary-looking boas if the two are mated.