Karyotype Characterization of Nine Periwinkle Species (Gastropoda, Littorinidae)

Abstract

Periwinkles of the family Littorinidae (Children, 1834) are common members of seashore littoral communities worldwide. Although the family is composed of more than 200 species belonging to 18 genera, chromosome numbers have been described in only eleven of them. A molecular cytogenetic analysis of nine periwinkle species, the rough periwinkles Littorina arcana, L. saxatilis, and L. compressa, the flat periwinkles L. obtusata and L. fabalis, the common periwinkle L. littorea, the mangrove periwinkle Littoraria angulifera, the beaded periwinkle Cenchritis muricatus, and the small periwinkle Melarhaphe neritoides was performed. All species showed diploid chromosome numbers of 2n = 34, and karyotypes were mostly composed of metacentric and submetacentric chromosome pairs. None of the periwinkle species showed chromosomal differences between male and female specimens. The chromosomal mapping of major and minor rDNA and H3 histone gene clusters by fluorescent in situ hybridization demonstrated that the patterns of distribution of these DNA sequences were conserved among closely related species and differed among less related ones. All signals occupied separated loci on different chromosome pairs without any evidence of co-localization in any of the species.

Genetic variation for adaptive traits is associated with polymorphic inversions inLittorina saxatilis

“…Littorina saxatilis does not seem to have heteromorphic sex chromosomes (García‐Souto et al. 2018) and the exact sex determining mechanism is unknown. In other systems, inversions are involved in the evolution of sex chromosomes (Rice 1987; Lenormand 2003; Connallon et al.…”

“…We set lodLimit = 16 since this resulted in 17 LGs as was expected based on chromosome number (García‐Souto et al. 2018). Additional singular markers that could not be assigned in this step were subsequently added using the “joinSingles2all” (using lodLimit = 16, lodDifference = 2) function with 21 iterations.…”

Proteomic similarity of the Littorinid snails in the evolutionary context

“…We applied this rationale to an example of the gastropods family Littorinidae (periwinkles), using the proteome as a molecular phenotype trait. These marine intertidal mollusks have been model objects for various studies in evolutionary biology, ecology and adaptation (Sokolova & Berger, 2000;Sokolova & Pörtner, 2001a;Sokolova & Pörtner, 2001b;Conde-Padín, Caballero & Rolán-Alvarez, 2009;Granovitch et al, 2009;Johannesson et al, 2010;Martínez-Fernández, De la Cadena & Rolán-Alvarez, 2010;Panova et al, 2010;Ng et al, 2011;Panova et al, 2011;Panova et al, 2014;Canbäck et al, 2012;Storey et al, 2013;Rolán-Alvarez, Austin & Boulding, 2015;García-Souto et al, 2018;Maltseva et al, 2016;Muraeva et al, 2016;Lobov et al, 2018;Lobov et al, 2015).…”

Peer Review #1 of "Proteomic similarity of the Littorinid snails in the evolutionary context (v0.1)"

“…We applied this rationale to an example of the gastropods family Littorinidae (periwinkles), using the proteome as a molecular phenotype trait. These marine intertidal mollusks have been model objects for various studies in evolutionary biology, ecology and adaptation [55][56][57][58][59][60][61][62][63][64][65][66][67][68][69][70][71][72][73] The relationships among the littorinid genera, the subgenera and "obtusata" and "saxatilis" clades are well resolved based both on morphology and several neutral DNA loci [74][75][76]. The hierarchy within the "saxatilis" species group still remains rather questionable, and these three species grouped in different combinations depending on the molecular approach used [e.g.…”