Final answer:
Alternate versions of a gene that can code for different traits are known as alleles. Alleles can be dominant or show varying effects based on gene dosage, affecting the phenotype of an organism with identical (homozygous) or different (heterozygous) alleles.
Step-by-step explanation:
The alternate versions of a gene found in a species of salamander that can code for different colors of spots, such as orange spots, yellow spots, or blue spots, are known as alleles. In genetics, an allele is one of several forms of the same gene that arise by mutation and are found at the same place on a chromosome. Alleles can exhibit complete dominance, where the wild-type allele is dominant over other mutants, or they can exhibit a form of dosage effect, which determines the phenotype based on the quantity of the gene product provided by either the wild-type or mutant alleles.
For example, in the case of the rabbit coat color gene, there are several alleles that determine the coat color, and the wild-type allele may supply a full dosage of fur pigment, whereas mutant alleles may provide a lesser dosage or none at all. Diploid organisms can be homozygous, carrying two identical alleles, or heterozygous, carrying two different alleles for a given trait.