We previously reported that mice lacking Spag6, which encodes the mammalian orthologue of the Chlamydomonas axonemal central apparatus protein PF16, exhibited a phenotype of both male infertility associated with severe sperm motility defects and axonemal structural abnormalities [12], demonstrating that loss of an axonemal central apparatus protein can have dramatic effects in mammals as well. The gene discussed is SPAG6; the disease is male infertility.