Thanks. I have never seen Rich's description. It would be interesting to know exactly what is occuring biochemically in a hypo/salmon. To this end it is a little misleading to term the trait as dominant (or co-dominant) since hypomelanism might actually be the simple loss (or near complete loss) of the function of one copy of a gene in the melanin synthesis pathway due to a single mutation. If this is the case, then it isn't really dominant since no gene product (or very little) is being produced, therefore, it is merely a loss of function mutation that can always be observed visually whether in the heterozygous or homozygous state. Then again, hypomelanism may be much more complicated and possibly involve inhibitors or activators of the melanin pathway either at the DNA level (transcription), at the RNA level (translation), or at the enzyme level.



>>There has been a lot posted on this topic lately. Sadly many believe the inaccurate information of old beliefs or marketing schemes. Here is a quote from Rich Ihle's article:

>>

>>"In the super salmon-to-super salmon crosses that have been performed in my facilities, all babies were scored as super salmon. These crosses verified our suspicions that salmon occurred both as homozygous (super salmon-same gene states) or heterozygous (salmon-different gene states) and thus supported the model o incommplete dominance as th;e mode of inheritance (Russell, 1990).

>>

>>Formal Test of the Model

>>By spring 1999, I had sufficient numbers of offspring (more than 350 individuals) from various crosses to test for a model of incomplete dominance (Russell, 1990). the results of our statistical tests showed strong support for this mode of inheritance (Ihle, Schuett and Hughes, 2000). Therefore, with respect to wild type, the salmon trait shows incomplete dominance and thus occurs in two forms: a heterozygous state (salmon) and a homozygous state (super salmon).

>>

>>Because the salmon trait is dominant, when it occurs in the heterozygous state it is expressed, although by way of one gene. In cases where a trait is inherited recessively, such as albinism in boas, individuals expressing the heterozygous state are identical in appearance to wild-type individuals." (Ihle 5,6)

>>

>>For anyone who didn't read this before, here it is written out. This information is very good to help people learning about genetics to understand how Heterozygous and Homozygous traits work. In addition, heterozygotes (animals that are heterozygous) carry one allele of any given trait, instead of a pair. In non Super Salmons/Hypos, they have one mutant allele for the hypomelanism trait and one for wild type. Hypo is dominant over wild so it is expressed even in heterozygous animals. Unlike in albinos, heterozygous individuals here appear normal because wild type is dominant over amelanism. The homozygotes of the Hypomelanistic trait are Super Hypos/Salmons.

>>

>>Thus is the reasoning behind DH Sunglow, or the pottential Quad Het as stated yesterday through breeding a Super Ghost X Super Arabesque Albino. In this case all would be quad het for Super Arabesque snowglow, the homozygous of Arabesque/Hypomelanistic/Anerythristic/Amelanistic.
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Rick Staub

R&R Reptiles

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