Abstract
Knowing the factors responsible for sex determination in a species has significant theoretical and practical implications; the dmrt1 gene (Doublesex and Mab-3 (DM)-related Transcription factor 1) plays this role in diverse animal species. Solea senegalensis is a commercially important flat fish in which females grow 30% faster than males. It has 2n = 42 chromosomes and an XX / XY chromosome system for sex determination, without heteromorph chromosomes but with sex proto-chromosome. In the present study, we are providing the genomic structure and nucleotide sequence of dmrt1 gene obtained from cDNA from male and female adult gonads. A cDNA of 2027 containing an open-reading frame (ORF) of 1206 bp and encoding a 402 aa protein it is described for dmrt1 gene of S. senegalensis. Multiple mRNA isoforms indicating a high variable system of alternative splicing in the expression of dmrt1 of the sole in gonads were studied. None isoforms could be related to sex of individuals. The genomic structure of the dmrt1 of S. senegalensis showed a gene of 31400 bp composed of 7 exons and 6 introns. It contains an unexpected duplication of more than 10399 bp, involving part of the exon I, exons II and III and a SINE element found in the sequence that it is proposed as responsible for the duplication. A mature miRNA of 21 bp in length was localized at 336 bp from exon V. Protein-protein interacting networks of the dmrt1 gene showed matches with dmrt1 protein from Cynoglossus semilaevis and a protein interaction network with 11 nodes (dmrt1 plus 10 other proteins). The phylogenetic relationship of the dmrt1 gene in S. senegalensis is consistent with the evolutionary position of its species. The molecular characterization of this gene will enhance its functional analysis and the understanding of sex differentiation in Solea senegalensis and other flatfish.
Highlights
Knowing the factors responsible for sex determination in a species has significant theoretical and practical implications
It should be noted that, with respect to the species cited above, the open-reading frame (ORF) of S. senegalensis is between 13% and 70% larger (13% more than in O. nitolicus; 41% more than in M. salmoides; 47% more than in Astyanax altiparanae; 58% more than in Dario rerio; and 70% more than in C. alburnus); this may be explained by the appearance of a duplication of exons II and III, which includes a partial duplication of the DM region
The genomic structure of the dmrt1 of S. senegalensis reveals a gene of 31400 bp composed of 7 exons and 6 introns
Summary
Knowing the factors responsible for sex determination in a species has significant theoretical and practical implications. Dmrt in Solea senegalensis managed better; and second, from an applied point of view, it is essential for implementing genetic improvement programs and obtaining monosex populations; this is especially useful when one sex grows significantly faster and/or larger than the other, as is the case with many fish [1, 2]. Chromosomal sex-determination systems appeared in vertebrates 180 million years ago and facilitated rapid adaptive radiation in species; the mechanisms of sex control vary widely among species [3]. Sex determination systems are especially variable in fish, and can be influenced by environmental factors (ESD) such as temperature, social environment, presence of contaminants or pH of the water or genetic factors (GSD) [6, 7] Whereas Sry (Sex determinant Y region) is considered the key regulator of sex determination in most mammals [4], in non-mammal vertebrates a common master regulator of sex has not been found, there are conserved genes such as Sox (SRY-box 9) and FoxL2 (Forkhead box L2) that act in a similar way in the regulation of sexual differentiation in all of them [5].
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