In blastocysts, the smaller transcript identified in Fig. 1d, that lacks exon 3, most likely represents the GTSF1-004 transcript (Transcript ID: OTTHUMT00000406189), a processed transcript that has no protein product and matches to ESTs (602638807 F1, 602552556 F1) that are derived from mucoepidermoid carcinoma and embryonal carcinoma, respectively. This evidence concerns the gene GTSF1 and embryonal carcinoma.