Human genes are preferentially encoded by codons that are less
likely to be mistranscribed (or "misread") into a STOP codon.
This finding by Brian Cusack and colleagues from the Max Planck
Institute for Molecular Genetics in Berlin and the CNRS in Lyon
and Paris is published in the open-access journal PLoS Genetics
on October 13th, 2011. Since the completion of the human genome
sequence over a decade ago, a multitude of studies have
investigated the forces that have shaped the genome over time.
However, because gene expression errors are not inherited, they
have been disregarded as an evolutionary force until now. In
biological systems, mistakes are made because the cellular
machinery is complex and error prone. The errors made in copying
DNA for transmission to offspring (genetic mutations) have so
far been the primary focus of molecular evolution. But errors
are much more frequent in the day-to-day task of gene
expression, for example in the transcription of DNA into RNA.
This study shows how human genes us