(A) RT-PCR survey using chicken Boule and Dazl specific primers on different tissues from adult rooster and hen (Gallus gallus). Dmrt1 (Doublesex and mab-3 related transcription factor 1) is a testis-specific gene and actin was used as a loading control. (B) RT-PCR survey using sea urchin-specific primers on different tissues from purple sea urchin (Strongylocentrotus purpuratus). Bnd (Bindin) is a testis-specific gene and ubiquitin was used as a loading control. W, water; Mu, muscle; Ki, kidney; He, heart; Br, brain; Li, liver; Ov, ovary; Te, testis; Am, Ampullae; Gu, guts. (C) Mouse Boule consists of 13 exons that encode multiple isoforms resulting from 5′ and 3′ alternative splicing. Two predominant mouse Boule isoforms – Bol1 and Bol2 – are male-biased and are restricted to or enriched in adult testes. Bol1 contains all 12 exons whereas Bol2 contains all exons except exon 11. RT-PCR analysis of RNA from mouse embryonic and adult gonads using primers corresponding to either exons 3 and 9 (upper panel, 501-bp band) or exons 3 and 12 (lower panel, 847-bp and 712-bp bands) reveals that full-length Bol1 is only expressed in postnatal testes, while Bol2 lacking exon 11 is also detectable at low levels throughout gonadal development in addition to its high adult testis expression. A similar pattern was confirmed using primers for exons 1 and exon 12.