From gene to protein

For protein-coding genes, DNA is first transcribed into RNA. The ribosome then reads the messenger RNA in codons and links the corresponding amino acids into a protein. Many genes instead produce functional RNAs that are not translated into proteins.

Key points

Transcription copies a gene into a messenger RNA inside the nucleus.
A codon consists of three bases; some codons signal the end of translation.
Proteins and functional RNAs carry out many different tasks in the cell.

#Transcription

When a gene is to be used, its section is transcribed into a messenger RNA, a mobile working copy. The DNA itself stays safe in the nucleus, only the copy travels out. This lets the same gene be read any number of times without using up the template. How often this happens is regulated, among other things, by the promoter.

#Translation

In the cytoplasm the messenger RNA threads through the ribosome. It reads the RNA in steps of three: each codon of three bases sets the next amino acid that is added to the growing chain. Once the chain is finished, it folds into the three-dimensional shape of the protein. Only this shape gives the protein its function.

#Why this matters for analysis

The central dogma, named so by Francis Crick in 1970, explains why a single letter change can do much or little. If it hits a codon such that a different amino acid is built in, the protein may change. If it hits a silent position, everything stays the same. Genome shows the letter, the interpretation of this effect is provided by the respective article.

What Genome measures. A variant can act at any stage: in the DNA, during RNA splicing or in the finished protein. That is why Genome explains for each gene what its product actually does.

Sources

1Crick, 1970 Central dogma of molecular biology. Nature 227:561-563. doi.org/10.1038/227561a0
2Brenner, Jacob & Meselson, 1961 An unstable intermediate carrying information from genes to ribosomes for protein synthesis. Nature 190:576-581. doi.org/10.1038/190576a0