Comparison of genome contents and transcriptome between the acidophile C. eustigma and neutrophile C. reinhardtii. (A) Venn diagram showing the number of protein families (by OrthoMCL) shared by C. eustigma, C. reinhardtii, and V. carteri genomes. (B) Gene orthologs of C. eustigma, C. reinhardtii, and V. carteri identified by OrthoMCL. “1:1:1” indicates an ortholog shared by three species as single copies; “N:N:N” indicates an ortholog shared by three species as multiple copies; “Patchy” indicates an ortholog shared by only two species. “ND” and “SD” indicate a species-specific gene in single or multiple copies, respectively. (C) Scatter plot of the mRNA levels of one-to-one orthologous genes between C. eustigma (pH 3.0, 20 °C) and C. reinhardtii (pH 7.0, 20 °C). The RPKM levels of 4,590 orthologous genes were plotted. (D) Comparison of RPKM levels of the PMA gene and HSP genes in C. eustigma (pH 3.0, 20 °C) and C. reinhardtii (pH 7.0, 20 °C). The number above the bar indicates the number of genes that exist in the respective nuclear genomes.