Heterozygous means that the two genes in a gene pair are different. This can mean that one gene is a normal gene and the other is a mutant gene. Or it can mean that the two genes are different mutant genes, such as lesser platinum//mojave.



A mojave ball python has a mojave mutant gene paired with a normal gene. Therefore a mojave ball python is heterozygous.



Most of the herper genetics web pages say that a heterozygous snake looks normal. The appearance of the heterozygous animal has nothing to do with whether an animal is heterozygous. The appearance of the heterozygous animal determines whether a mutant gene is dominant, codominant or recessive to the normal gene.



When a heterozygous snake looks normal, then the mutant gene is recessive to the normal gene. When a heterozygous snake does not look normal, then the mutant gene is not recessive to the normal gene.



When a heterozygous snake looks like the homozygous mutant type, then the mutant gene is dominant to the normal gene. When a heterozygous snake does not look normal and does not look like the homozygous mutant type, then the mutant gene is codominant to the normal gene. This is the ideal classification. Nature can be sloppy, though. Sometimes a heterozygous individual can look like the homozygous mutant type and sometimes abnormal but not like the homozygous mutant type. In these cases it is probably better to call the mutant dominant to the normal gene.



I'll get back on the other questions.



Paul Hollander

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