Genetic diversity of marbled goby populations in the Anatolian coasts of the north-eastern Mediterranean

Abstract

The demographic histories, genetic relationships and population structure of sedentary fish Pomatoschistus marmoratus (Risso, 1810), which was sampled from the north-eastern basin of the Mediterranean Sea (including the Turkish coasts of the Black Sea, Aegean Sea, Levantine Sea and Sea of Marmara), were investigated by mitochondrial cytochrome c oxidase subunit I (652 bp) and cytochrome b (526 bp) regions. It was found that the population groups had high haplotype diversity while the nucleotide diversity was quite low for both gene regions. Phylogeographic analyses of the haplotypes indicated that the Levantine population (LEV) were genetically different from other populations. Also, the gene flow between LEV and the other populations was very limited. The results of the analyses of neutrality and mismatch distributions that were applied to the population groups were evaluated as a whole. It was determined that the haplogroup that represents the Black Sea and Sea of Marmara populations (BLAMAR) was stable, but the Levantine population (LEV) was under the sudden demographic expansion model following the population bottleneck. The genetic variance indices indicated sudden demographic expansion following population contraction. This was supported by star-shaped haplotype networks. The reason for this limited gene flow and differentiation between the Levantine population (LEV) and the others was linked with wind-driven offshore transport of the larvae and surface currents in these sub-basins. The timing of the differentiation, demographic histories of populations associated with geological and palaeo-climatic events and current ecological conditions were discussed.

Cytochrome b Sequencing as a Tool for Identification of Morphologically Similar Mediterranean Gobies Gobius incognitus and Gobius bucchichi (Actinopterygii: Gobiidae)

“…Mitochondrial gene cytochrome b (cyt b) was used for the identification, considering the relatively high divergence between both species on this marker observed by Kovačić & Šanda [18]. Cyt b was confirmed to be a useful marker for species delimitation in gobies, e.g., [9,18,32], reconstruction of phylogenetic relationships between species e.g., [31,[34][35][36], as well as for studying phylogeography and population genetics e.g., [37,38,40,42,43]. Cyt b was amplified by polymerase chain reaction (PCR) using PPP Master Mix (Top-Bio, Praha, Czech Republic) following primers and protocols described in Šanda et al [44].…”

“…Most of the studies focused on taxonomy or distribution, e.g., [4][5][6][7][8][9]11,12,14,15,18,28,[30][31][32]. Several studies deal with phylogenetic relationships, e.g., [33][34][35][36], and also the population genetic structure and phylogeography were investigated for several species, e.g., [37][38][39][40][41][42][43].…”

Different Interspecies Demographic Histories within the Same Locality: A Case Study of Sea Cucumbers, Cuttlefish and Clams in Greek Waters

“…However, to the best of our knowledge, this study represents the first report concerning the eastern basin of the Mediterranean Sea, which examines genetic diversity between various Sepia officinalis (cuttlefish) (Linnaeus, 1758), Holothuria tubulosa (sea cucumber) (Gmelin, 1791), and Venus verrucosa (clam) (Linnaeus, 1758) populations that inhabit different marine areas in the North Aegean Sea. Nevertheless, studies within the North Aegean Sea show different patterns for a variety of marine organisms, revealing either high connectivity [26], limited dispersal abilities, or strong barriers to gene flow [27], showing contrasting patterns of gene flow and adaptive genetic variation. Regional heterogeneity aside, the latter may be due to species ecology (e.g., larval settlement) [7] or high selection pressures (e.g., pathogens) [4,28].…”