Evidence for a Robertsonian fusion in Solea senegalensis (Kaup, 1858) revealed by zoo-FISH and comparative genome analysis

Abstract

BackgroundSolea senegalensis (Kaup, 1858) is a commercially important flatfish species, belonging to the Pleuronectiformes order. The taxonomy of this group has long been controversial, and the karyotype of the order presents a high degree of variability in diploid number, derived from chromosomal rearrangements such as Robertsonian fusions. Previously it has been proposed that the large metacentric chromosome of S. senegalensis arises from this kind of chromosome rearrangement and that this is a proto-sex chromosome.ResultsIn this work, the Robertsonian origin of the large metacentric chromosome of S. senegalensis has been tested by the Zoo-FISH technique applied to two species of the Soleidae family (Dicologlossa cuneata and Dagetichthys lusitanica), and by comparative genome analysis with Cynoglossus semilaevis. From the karyotypic analysis we were able to determine a chromosome complement comprising 2n = 50 (FN = 54) in D. cuneata and 2n = 42 (FN = 50) in D. lusitanica. The large metacentric painting probe gave consistent signals in four acrocentric chromosomes of the two Soleidae species; and the genome analysis proved a common origin with four chromosome pairs of C. semilaevis. As a result of the genomic analysis, up to 61 genes were annotated within the thirteen Bacterial Artificial Chromosome clones analysed.ConclusionsThese results confirm that the large metacentric chromosome of S. senegalensis originated from a Robertsonian fusion and provide new data about the chromosome evolution of S. senegalensis in particular, and of Pleuronectiformes in general.Electronic supplementary materialThe online version of this article (10.1186/s12864-018-5216-6) contains supplementary material, which is available to authorized users.

Genome and Phylogenetic Analysis of Genes Involved in the Immune System of Solea senegalensis – Potential Applications in Aquaculture

“…The hybridizations agree with the results obtained for the BAC clones tlr8, calr, lysg and mx that had already been located (Ponce et al, 2011; García-Cegarra et al, 2013; Merlo et al, 2017; García-Angulo et al, 2018). In our study, candidate genes tlr3 and tlr8 were found in different chromosomes.…”

“…Of the 14 BAC clones analyzed, nine BAC clones were sequenced with a total of 80 genes annotated, and the other five BAC clones had been sequenced previously (Ponce et al, 2011; García-Cegarra et al, 2013; Merlo et al, 2017; García-Angulo et al, 2018). In total, 109 genes were annotated and 24 of the 109 genes (22.01%) were found to be related to the immune system (Table 1).…”

“…Chromosome preparations were obtained according to García-Angulo et al (2018). To prepare FISH probes, BAC clones were grown on LB containing chloramphenicol, at 37°C, overnight.…”

The genomic structure of the highly-conserved dmrt1 gene in Solea senegalensis (Kaup, 1868) shows an unexpected intragenic duplication

“…rhombus , which present a karyotype with 2n = 44 chromosomes including two metacentric pairs [ 31 ]. The origin of this chromosome has also been confirmed by Zoofish data obtained from two species of the Soleidae family ( Dicologlossa cuneata and Dagetichthys lusitanica ), and by comparative genome analysis with Cynoglossus semilaevis [ 32 ].…”

“…To investigate the structure of the dmrt1 gene in the genome, a BAC sequence from clone 48K7 [ 32 ] was used. The dmrt1 cDNA of S .…”