It is often useful to distinguish the two strands of DNA -- the strand that is copied into mRNA and subsequently translated has the mRNA complementary sequence to the mRNA, while the base sequence of the opposite strand directly corresponds to the codons in the mRNA.

The terms template strand, sense strand, and coding strand are commonly used to describe one of the two strands of DNA, however the nomenclature is quite confusing because different authors have used these terms to describe both strands -- one school argues that the strand copied into mRNA should be considered the template strand, but the other school argues that the opposite strand which reflects the sequence in the mRNA should be considered the template because the corresponding codons are copied into protein. The first definition is used in the figures below, however, to avoid confusion, when using the words template, sense, or coding, it is essential to explicitly define how you are using the terms. I believe that these terms are best defined as described below.

The term template strand refers to the sequence of DNA that is copied during the synthesis of mRNA.

The opposite strand (that is, the strand with a base sequence directly corresponding to the mRNA sequence) is called the coding strand or the mRNA-like strand because the sequence corresponds to the codons that are translated into protein.

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