What does 'degenerate code' refer to in genetics?

In genetics, the term 'degenerate code' specifically refers to the redundancy of the genetic code. This means that multiple codons (three-nucleotide sequences) can code for the same amino acid. For example, the amino acid leucine can be encoded by six different codons (UUA, UUG, CUU, CUC, CUA, CUG). This redundancy is crucial because it provides a buffer against mutations; changes in the DNA sequence may not necessarily lead to changes in the resulting protein since several codons can yield the same amino acid.

While variability of amino acids is related to the genetic code in terms of the different possible amino acids, it does not specifically describe the concept of degeneracy. The idea of coding for only essential genes does not pertain to the redundancy of codons but rather to the expression of genes necessary for survival. Lastly, uniformity across species might refer to conserved genetic sequences, but it does not encapsulate the redundancy present within the genetic code itself. Thus, the redundancy that allows for different codons to specify the same amino acid is what defines the degenerate nature of the genetic code.