A section within a strand of messenger RNA containing a nucleotide triplet that codes for no amino acid. Nonsense cannot be read during protein synthesis and so terminates the polypeptide chain.

• 无意义突变，无意义密码在一条包含有为无氨基酸指定遗传密码的核苷酸组的信使核糖核酸中的一部分，无意义密码在蛋白质合成期间不能被读出，因此使肽链终止