High connectivity of the white seabream (Diplodus sargus, l. 1758) in the aegean sea, eastern mediterranean basin

Population dynamics in the marine realm can shape species’ spatial structure and genetic variability between given geographical areas. Connectivity is an important factor of species’ population structure. In this study, we examined the genetic diversity and structure of white seabream (Diplodus sargus, L. 1758) in the eastern Mediterranean basin, using a panel of four microsatellite markers. Recorded low FST values within the study area indicate little evidence of genetic differentiation among populations. Results suggest high gene flow which may imply near-panmixia between populations, indicating the possibility of a probable movement of adult migrants, or strong passive drift at sea in early life stages of the species. To this extent, bibliographically speaking, different species within the Sparidae family favor altered population dynamics patterns with respect to local populations and genetic divergence, in the context of the molecular marker used. © 2019 by the authors. Licensee MDPI, Basel, Switzerland

Genetic diversity and structure of Cymodocea nodosa meadows in the Aegean sea, eastern Mediterranean

Genetic diversity and structure were investigated among seven meadows of Cymodocea nodosa in the Aegean Sea, eastern Mediterranean basin. Analysis of three genetic loci, corresponding to the nuclear rDNA operon, revealed 12 distinct multilocus RFLP genotypes. The observed FST pairwise values revealed, in most cases, a previously unidentified genetic diversity in Aegean populations. A relative sub-structuring was revealed within Pagassitikos gulf, suggesting a fragmentation possibly due to the significant factor of the previously recorded cyclonic system within the studied gulf. Moreover, individual-based landscape approach analysis supports the latter observation, suggesting the presence of three different sub-populations overall in the studied area. The observed barriers maybe related to angiosperms re-colonization from warmer parts of the eastern Mediterranean, after the last glacial maximum. AMOVA indicated the existence of hierarchical significant genetic variation between meadows within gulfs and among samples within meadows, rather than between the two gulfs, as a potential consideration for unidentified limited dispersal and demographic habits of the species in question. On the other hand, sexual reproduction events may contribute to the maintenance of genetic diversity of C. nodosa structuring in the Aegean Sea, where the species is also exhibiting extensive morphological plasticity. © 2016, ALÖKI Kft., Budapest, Hungary

Population structure of two benthic species with different larval stages in the eastern mediterranean sea

Population structure in the marine environment is sometimes cryptic due to complex demographic expansion and distribution of the species. Benthic organisms possess different reproductive strategies with regards to larvae dispersal ability. The hypothesis of variation in biogeographic structure in two benthic species, sea urchin Paracentrotus lividus and ascidian Microcosmus saba-tieri using Random Amplifed Polymorphism (RAPD) was tested. Analyses indicate near panmixia and low but significant genetic differentiation between Amvrakikos Gulf and open sean P. lividus, mostly attributed to the documented nanism in the area. M. sabatieri populations showed substantial genetic differentiation over a latitudinal gradient. Results suggest that benthic species with a long-lived larval phase favour large geographical dispersal while those with a short-lived phase utilise a shorter dispersal range

Heterozygosity fitness correlations and generation interval of the Norway lobster in the Aegean Sea, eastern Mediterranean

Background: Comprehensively detailed information on population dynamics for benthic species is crucial since potential admixture of individuals could shift the genetic subdivision and age structure during a full breeding period. The apparent genetic impact of the potential recruitment strategy of Norway lobster Nephrops norvegicus is still under research. For this reason the present study was focused on genetic variation of the species over a given continuous year period in a semi-enclosed gulf of the Aegean Sea. Results: Analyses revealed that the relative smaller size class in females and the apparent faster growth of males may represent a key-role differential strategy for the two sexes, whereas females tend to mature slower. Heterozygosity fitness correlations (HFCs) showed substantially significant associations suggesting that inbreeding depression for females and outbreeding depression for males are the proximate fitness mechanisms, respectively. Conclusions: Nephrops norvegicus uniformal genetic composition (background of high gene flow), could be attributed to potential population recolonization, due to a hypothesized passive larval movement from deeper waters, which may suggest that some offspring of local residents and potential male non-breeders from other regions admixture randomly. © The Author(s) 2019. This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated