Comparison of the numbers of genes found to be enriched in human ES-cell lines in the five studies [1-5]. The circles each represent the number of genes found to be enriched in each cell line; the inner light circles represent genes shared with mouse cell lines (mouse genes not shared with human cell types are omitted. (a) Sperger et al.  compared five human ES-cell lines with seminoma and embryonal carcinoma (EC) cells and found 330 genes in common between them all. (b) Sato et al.  found 227 genes in common between human and mouse ES cells. (c)Richards et al.  found 192 genes that were upregulated in human ES cells compared with other human and mouse SAGE libraries. (d) Abeyta et al.  found 76 genes in common between three human ES-cell lines and mouse ES cells. (e) Zeng et al.  found 92 genes in common between two human ES-cell lines and mouse ES cells. In (b-d), the inner light circles represent the number of candidate pluripotency genes; in (a), candidate pluripotency genes are those shared by human ES and EC cells but not seminoma cells (565 genes).