Why is the percentage similarity in the gene always lower than the percentage similarity in the protein for each of the species? (Hint: Recall how a gene is expressed to produce a protein.)

Question

anonymous · Answer

There are four nucleic bases that can be combined to make 64 possible three letter codons (triplets). However there are only the 20 essential amino acids (plus stop codons). This results in multiple codons recognizing & binding the same tRNA (bearing the same amino acid). Synonyms in the genetic code exist and some species tend to use one synonym rather than another to get the same amino acid sequence. 

-gardengallivant