GC (A) and AT (B) skews across genes in unicellular fungi. Open reading frames are divided into 40 bins from the ATG to the stop codon, data for each species is pooled and the GC and AT skew calculated for each bin. The 200 bp upstream and downstream are also included. In almost all species we see a clear pattern of C-bias in the start of the gene changing sign to a G-bias towards the end. AT skews are flat but almost always positive.