A complementary DNA clone for an .alpha.-tubulin was isolated from a mouse testis complementary DNA library. The untranslated 3'' end of this complementary DNA is homologous to 2 RNA transcripts present in postmeiotic cells of the testis but absent from meiotic cells and from several tissues including brain. Temporal expression of this .alpha.-tubulin complementary DNA provides evidence for the haploid expression of a mammalian structural gene.