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How do DNA sequences provide instructions for making proteins?

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Vaccine development — genetic engineering The generation of vaccines relies heavily on techniques in genetic engineering.

DNA sequences provide instructions for making proteins through a two-step process: transcription and translation.1

First, during transcription, the genetic information stored in a specific segment of DNA is copied into a single-stranded molecule called messenger RNA (mRNA). This process uses the base-pairing rules of DNA, where specific nucleotides in the DNA template strand direct the incorporation of complementary bases into the mRNA chain.21

Second, during translation, the mRNA serves as a template for protein synthesis. The sequence of the mRNA is read by ribosomes in nonoverlapping groups of three nucleotides known as codons. Each codon specifies a particular amino acid or acts as a stop signal. As the ribosome moves along the mRNA, transfer RNA (tRNA) molecules bring the corresponding amino acids to the ribosome, where they are linked together to form a polypeptide chain that folds into a functional protein. This relationship between the nucleotide sequence and the amino acid sequence is known as the genetic code.3425