The Sex-Specific Splicing of Doublesex in Brine Shrimp Artemia franciscana .

The understanding of sex determination and differentiation in animals has recently made remarkable strides through the use of advanced research tools. At the gene level, the Mab-3-related transcription factor ( Dmrt ) gene family, which encodes for the typical DNA-binding doublesex/Mab-3 (DM) domain in their protein, is known for its contribution to sex determination and differentiation in insects. In this study, DNA-binding DM domain screening has identified eight transcripts from Artemia franciscana transcriptomic that encode proteins containing one conserved DNA-binding DM domain. The genome mapping confirmed that these eight transcripts are transcribed from six different loci on the A. franciscana genome assembly. One of those loci, the Af.dsx-4 locus, is closely related to Doublesex , a gene belonging to the Dmrt gene family. This locus could be transcribed into three alternative transcripts, namely Af.dsx 4 , Af.dsx F and Af.dsx M . While Af.dsx 4 and Af.dsx F could putatively be translated to form an identical Af.dsx F protein of 186 aa long, Af.dsx M translates for an Af.dsx M protein of 289 aa long but shares a DNA-binding DM domain. Interestingly, Af.dsx F and Af.dsx M are confirmed as sex-specific transcripts, Af.dsx F is only present in females, and Af.dsx M is only present in male individuals. The results suggest that the sex-specific splicing mechanism of the doublesex described in insects is also present in A. franciscana . Af.dxs-4 locus can be used in further studies to clarify the sex determination pathways in A. fracnciscana .