GC content of genic regions and overall genome assemblies. For each gene, the GC content (percent G + C nucleotides) of genomic regions containing the gene was determined as described in methods. The cumulative distributions of GC content for overall genome assemblies (thin red line for Amel 4.5 and thin black line for Amel_2.0) show that the Amel_4.5 assembly has a higher fraction of low GC content regions than does the Amel_2.0 assembly (note the thin red line is to the left of the thin black line below about 28% GC). The cumulative distributions of GC content for the regions containing genes (thick red line for all OGSv3.2, thick green line for Previously known genes, thick blue line for Type I New genes and thick pink line for Type II new genes) show that regions containing genes are lower in GC content than the overall genome. This trend applies for the complete set of OGSv3.2 genes, as well as the three subsets. The distribution for Type I New genes lies to the left of the other distributions, showing that Type I New genes are located in lower GC content regions than the other gene subsets. The distribution for Type II new genes is to the right of the distributions for the other gene subsets, showing that the Type II New genes are located in higher GC content regions.