Which of the following is not a property of the genetic code?

Characteristics of the genetic code: 1. It is a triplet code. Each threenucleotide codon in the mRNA specifies one amino acid. 2. It is comma free and mRNA read three bases at a time without skipping any bases. 3. It is non-overlapping/non or ambiguous. Each nucleotide is a part of only one codon and is read only once during translation. 4. It is almost universal. In nearly all organisms, most codons have the same amino acid meaning. 5. It is degenerate, means among 20 amino acids, 18 are encoded by 2 or more codons. 6. The code has start and stop signals. AUG is the usual start signal and defines the open reading frame. 7. Stop signals are codons with no corresponding $t$ RNA. Stop signals are also known as nonsense or chain-terminating codons. There are generally three stop codons: UAG, UAA, and UGA.