Many germ cell-specific variants of general transcription factors (GTFs) have evolved. Only factors are shown for which a role has been documented. While TBP dominates transcription in somatic cells (A) and is also expressed in testis (C), it is completely replaced by TBP2 in female germ cells (B). Male germ cells express high levels of TLF and a vital share of transcription in these cells is dependent on this factor. Similarly TFIIA is replaced completely in oocytes and partially in sperm by ALF. Variants of TFIID contain germ cell-specific TAFs.