In humans, there are potentially 512 functional tRNA genes.
These 512 genes cover the 21 amino acids that are used in protein synthesis. It's important to understand that this refers to the number of tRNA genes and not necessarily the number of different tRNA molecules. Many different tRNA genes can code for tRNAs that carry the same amino acid (isoacceptors), each recognizing different codons. The number of genes for a single tRNA isoacceptor can vary greatly.
Therefore, while there are approximately 512 functional tRNA genes in the human genome, the actual number of distinct tRNA molecules may be different due to post-transcriptional modifications and other factors.
