First approach to studying the genetics of the meagre (Argyrosomus regius; Asso, 1801) using three multigene families

Abstract

The meagre (Argyrosomus regius) is a commercially important species for fisheries, and aquaculture production has been increasing in recent years. However, this growing importance has not been matched by increased genetic knowledge of the species. For this reason, an initial approach has been made to understanding the genetics of the meagre, using three particular multigene families (45S and 5S ribosomal DNA and U2 snRNA gene) as both molecular and cytogenetic markers. Only one type of 5S rDNA and only one ITS-1 (from 45S rDNA) were obtained, and these therefore could provide the basis for the development of genetic markers for this species. However, the U2 snRNA gene produced a multi-band electrophoretic pattern, and some of these bands were demonstrated to be linked with the U1 snRNA gene. This linkage could also provide a good species-specific marker which could be useful for tracing the evolutionary history of the Sciaenidae family. In this study, we have described for the first time the karyotype of the meagre: this is composed of 48 acrocentric chromosomes. Each of the three gene families were localized on different chromosome pairs, although the U2 snRNA gene probe was also located scattered throughout the genome of the meagre, as expected by the amplification pattern.

Molecular Cytogenetic Analysis of the European Hake Merluccius merluccius (Merlucciidae, Gadiformes): U1 and U2 snRNA Gene Clusters Map to the Same Location

“…The presence of signals at a single location in one chromosome pair for the 45S rDNA in M . merluccius is concordant with results obtained in more than 70% of the species of teleosts analyzed [ 17 , 21 , 23 , 31 , 35 , 53 , 54 ]. On the contrary, the intercalary position of the cluster found in the European hake is rare among teleosts, 87% of which show subterminal NORs [ 17 ].…”

“…Chromosomal mapping of ribosomal RNA genes has been performed in many species of fishes [ 15 – 17 , 20 – 22 , 24 , 26 , 31 – 36 , 49 – 54 ]. The presence of signals at a single location in one chromosome pair for the 45S rDNA in M .…”

“…The genomic organization of the snRNA genes (snDNA), the genes expressing the U snRNAs, shows considerable variation in eukaryote genomes [ 29 ]. Molecular analysis of U1 and U2 snRNA genes in fishes indicate that, at least in a few species, some of the copies of these genes are linked [ 19 , 29 – 31 ] but no FISH mapping evidence has corroborated so far that linkage. U1 snRNA genes have been mapped by FISH to a single location on the chromosomes of 19 species of cichlid fishes [ 19 ] and to three chromosome pairs in five species of Astyanax [ 24 ].…”

“…U1 snRNA genes have been mapped by FISH to a single location on the chromosomes of 19 species of cichlid fishes [ 19 ] and to three chromosome pairs in five species of Astyanax [ 24 ]. On the other hand, U2 snRNA genes cluster at one or more chromosomal locations in 24 species of teleosts belonging to the families Batrachoidiae [ 32 ], Gymnotidae [ 33 ], Moronidae [ 34 ], Spardidae [ 21 ], Scianidae [ 31 ], Bagridae [ 35 ], Haemulidae [ 36 ] and Characidae [ 24 ].…”

Evidence for 5S rDNA Horizontal Transfer in the toadfish Halobatrachus didactylus (Schneider, 1801) based on the analysis of three multigene families

“…punctatus [51], and A . regius [52] all showed a close linkage with another member of the U snRNA family. This linkage has been applied as a useful tool for the identification of different species of sole [53].…”