What is a variety of genetic code that does not create a phenotype called?

The term that describes a variety of genetic code that does not create a phenotype is a neutral allele. Neutral alleles are changes in the DNA sequence that do not have any significant impact on the organism's observable traits or phenotypes. This is often due to the nature of the genetic code, where some mutations or variations are silent, not leading to any functional changes in the protein that is produced.

Recessive alleles, while they may not express a phenotype in a heterozygous pairing, can lead to specific characteristics when homozygous. Dominant alleles express their traits even when only one copy is present, thus clearly contributing to the phenotype. The term "phenotypic allele" isn't standard in genetics and doesn't accurately define a category of alleles based on their expression or the lack thereof. Neutral alleles, therefore, uniquely fit the description of not influencing the phenotype at all.