To expand on that a little, many hundreds to several thousands of codons make up one gene. So if a codon is equivalent to a letter in the alphabet, a gene is the equivalent of from several paragraphs to several pages of text.

It takes many normal genes to produce normal pigmentation. These include the normal version of the Kahl albino mutant gene, the normal version of the Sharp albino mutant gene, the normal version of the salmon mutant gene, the normal version of the caramel albino mutant gene, the normal version of the various tyrosinase-positive albino mutant genes, etc. You can think of the process as an assembly line. If all the machines in the line are working as expected, the product coming off the end of the line is normal. If one machine in the line is malfunctioning, the product is somehow abnormal. If a different machine in the line is malfunctioning, the product coming off the end of the line is abnormal, but in a different way.

Kahl albino is a single mutant trait because it requires only one change from normal to produce a Kahl albino. All the many thousands of normal genes at the other locations in the genome are still there, but they are ignored for simplicity.

You might want to read up on the wild type concept in genetics. Wild type is the most common phenotype and the most common gene at each locus in the wild population. Wild type is also the standard of comparison.

Paul Hollander

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