Central Dogma Engine
DNA → mRNA → protein, and what happens when you break it
Transcribe and translate a real gene, shift the reading frame, then mutate any base and watch the tool classify the damage.
The takeaway
The same physical event, one base changing, can be harmless or catastrophic. The genetic code's structure, not the mutation itself, decides which.
RNA polymerase reads the template strand 3'→5' and builds the mRNA 5'→3'. Because the mRNA is the complement of the template, it ends up identical to the coding strand, just with uracil in place of thymine.
The ribosome reads three bases at a time, but where it starts decides everything. Shift the start by one base and every downstream codon is re-sliced into a different triplet, a completely different protein. Translation begins at the first AUG.
Unmutated sequence
Click any base below to substitute it, or use Insert / Delete to shift the reading frame. The verdict will update instantly.
Click a base to select it, then substitute, insert, or delete. Codon boundaries follow frame +1. The start codon is green, the stop codon red, and mutated bases are ringed in amber.
Ribosome starts at codon 1 (AUG) and produces a 22 aa peptide, terminating at the stop codon.
Reading the variant, not the gene
Clinical genomics is mostly this exercise at scale: a patient variant is classified as silent, missense, nonsense or frameshift, and that class is the first evidence for whether it is benign or pathogenic. One base, HBB codon 7, is the difference between healthy haemoglobin and sickle-cell disease.Frameshifts are the knockout tool
CRISPR cuts DNA and the cell repairs it sloppily by NHEJ, inserting or deleting a base or two. If the indel is not a multiple of three, the frame shifts, a premature stop appears, and the gene is dead. That is how most gene knockouts and most functional-genomics screens actually work.Codon choice is engineering
Because the code is degenerate, the same protein can be encoded many ways. Codon optimisation, choosing synonymous codons the host cell translates fastest, is standard practice for protein manufacture and for mRNA vaccines, where it changes yield by orders of magnitude without touching the protein.
The central dogma: information flows DNA → RNA → protein, with polymerases and the ribosome doing the copying.
Image: Dhorspool, Wikimedia Commons (CC BY-SA 3.0)