If both strands of the DNA are complementary why complementary codons don’t codify for the same amino acid?


If I read a strand rather than the other I should obtain regardless the same protein, but I checked and the codons are not complementary. So if on a strand I have CGC (alanine) the other should code too for alanine but complementary GCG codes for arginine. Am I missing something?

In: Biology

On the DNA strand for any given gene, there is a strand that is “read” to generate mRNA, and a strand that is just there as a template for the other strand.

These aren’t always the same strand for different genes.

There are signals in the DNA around the gene that help the transcription proteins orient themselves correctly, so that only the correct strand is read.

Don’t forget that you read each strand in a different direction. The ribosomes receive instructions about where and in what way a gene is to be read by promoters and other helpers. It’s the same way you can have multiple proteins be read from the same sequence.