By Melissa Mayer
Updated Aug 30, 2022
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When you think about your genetic material, you probably picture the genes responsible for your eye color or your height. While DNA determines your appearance, it also encodes all the molecules that keep your body functioning. To translate this blueprint, the cell uses messenger RNA (mRNA) to shuttle genetic information from the nucleus to the cytoplasm.
Double‑stranded DNA uses base pairs A‑T and G‑C. During transcription, RNA polymerase reads the template strand and creates a single‑stranded mRNA that mirrors the coding strand, replacing every T with U. For example, DNA coding strand AGCAATC pairs with template strand TCGTTAG, and the resulting mRNA is AGCAAUC.
Transcription is the process by which RNA polymerase binds to DNA, unwinds a short region, and synthesizes a complementary RNA strand. The enzyme reads the template strand, producing an mRNA sequence that mirrors the coding strand. This mRNA exits the nucleus and carries the genetic message to the cytoplasm, where ribosomes translate it into proteins.
DNA consists of four nucleotides: adenine (A), thymine (T), guanine (G) and cytosine (C). In the double helix, A pairs with T and G pairs with C. The two strands are called the coding (sense) strand and the template (antisense) strand. For instance, if the coding strand reads AGCAATC, the template strand must contain the complementary bases, TCGTTAG.
The key difference between DNA and mRNA is the substitution of thymine (T) with uracil (U). Since mRNA is single‑stranded, it does not form a double helix, so the U substitution simplifies the translation process. Using the template strand TCGTTAG, RNA polymerase synthesizes the mRNA AGCAAUC. Notice how the mRNA matches the coding strand except for the T→U change.
Understanding the sequence transformations from coding DNA to template DNA to mRNA is essential for grasping how proteins are made. Even a single base change can alter a protein’s structure, potentially leading to disease. By studying these small variations, researchers can uncover the genetic basis of conditions and develop targeted therapies.
Your DNA not only determines visible traits but also dictates the molecules your body builds. Mastering the transcription process is the first step toward decoding cellular function.
