Mitochondrial DNA in Atherina (Teleostei, Atheriniformes): differential distribution of an intergenic spacer in lagoon and marine forms of Atherina boyeri

Abstract

The big-scale sand smelt Atherina boyeri lives in fresh water, brackish water and sea water of the western Atlantic Ocean and Mediterranean Sea. Previous studies concerning distribution, biometric characters and genetic molecular markers have suggested the possible existence of two or even three different groups or species of sand smelt, one 'lagoon' type and one (or twopunctuated and non-punctuated on the flanks) 'marine' type. In this study, the presence and the localization of an insertion was described, c. 200 bp in length, in the mtDNA of the lagoon and marine punctuated specimens of A. boyeri and its absence in the marine non-punctuated specimens, as well as in other two congeneric species, Atherina hepsetus and Atherina presbyter, and in the atheriniform Menidia menidia. The intergenic spacer is located between the tRNA Glu and cytochrome b (cyt b) genes and shares a c. 50% sequence similarity with cyt b. The distribution and the features of the intergenic spacer suggest that it might have originated from an event of gene duplication, which involved the cyt b gene (or, more likely, a part of it) and which took place in the common ancestor of the lagoon and the marine punctuated specimens. The data obtained therefore support the hypothesis of the existence of three cryptic and, or sibling species within the A. boyeri taxon and provide a genetic molecular marker to distinguish them.

Some Marine Tunisian Atherina boyeri Populations (Teleostei) have Morphological and Molecular Characteristics of Lagoon Fishes

“…2B) clearly distinguish a group constituted by island and lagoon fish plus French populations of A. punctuata. Interestingly, an insertion of c. 200 bp in length has been found in the same localisation in the mtDNAs of both lagoon and marine punctuated fishs but not in the marine nonpunctuated specimens, as well as in other two congeneric species, A. hepsetus and A. presbyter, and in the atheriniform Menidia menidia [50]. This intergenic spacer is located between the tRNA(Glu) and cyt b genes, and shares approximatly 50% sequence similarity with cyt b, suggesting that it might have originated from an event of gene duplication involved at least a part of the the cyt b gene and which took place in the common ancestor of the lagoon and the marine punctuated specimens, confirming our morphological and phylogenetic results.…”

Pseudoplatystoma metaenseandP. orinocoense(Siluriformes: Pimelodidae) from the Orinoco basin, Venezuela: cytogenetic and molecular analyses

“…For a subset of 10 specimens (five P. metaense and five P. orinocoense), fragments of the cyt b and COI mitochondrial genes were amplified. DNA was isolated from white muscle preserved in 95% ethanol and amplified through polymerase chain reaction using primers GluFor (Milana et al 2008) and H15913 (Minegishi et al 2005) for cyt b, and FishF1 and FishR2 (Ward et al 2005) for COI following the procedures reported by Milana et al (2008). The sequences obtained were deposited into the GenBank database (Acc.…”

Multilocus phylogenetic analysis of the genus Atherina (Pisces: Atherinidae)

“…These findings are consis- Moreover, the present results reveal a closer relationship between brackish/lagoon A. boyeri and punctated fish, with this group being sister to non-punctated specimens. In their analysis of portion of the mitochondrial cytochrome b, Milana et al (2008) detected the presence of an insertion, common to lagoon and punctuated forms of A. boyeri. The agreement between biometric and genetic characters (both mitochondrial and nuclear) and the wide distribution of the three entities represent, in our view, very strong support for the recognition of three different species.…”