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

Dilruba Seyhan-Ozturk,Semih Engin

doi:10.1017/s0025315421000199

Abstract

AbstractThe 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.

Highlights

The semi-enclosed Mediterranean Sea underwent substantial changes due to its evolutionary history throughout the Tertiary period
Recent research, which describes genetic differentiation in some Mediterranean species, has indicated that habitats, biological and oceanographic conditions have a great impact on population structures, in addition to climatic changes and geological events (Avise, 2000; Lemaire et al, 2005; Maggio et al, 2009; Mejri et al, 2011)
A total of 326 P. marmoratus specimens were sampled from 16 localities in the north-eastern Mediterranean (Turkish coasts of the Black Sea, Aegean Sea, Levantine Sea and Sea of Marmara) (Figure 1)

Summary

Introduction

The semi-enclosed Mediterranean Sea underwent substantial changes due to its evolutionary history throughout the Tertiary period. Combined effects of the complex geological events, and palaeo-climatic history of the Mediterranean Sea, play a key role in shaping speciation and population structuring (Patarnello et al, 2007). Recent research, which describes genetic differentiation in some Mediterranean species, has indicated that habitats, biological and oceanographic conditions have a great impact on population structures, in addition to climatic changes and geological events (Avise, 2000; Lemaire et al, 2005; Maggio et al, 2009; Mejri et al, 2011). Research on Pomatoschistus species and populations has revealed that there is a high genetic differentiation between both the western and eastern Mediterranean Sea and Atlantic–Mediterranean populations of these species (Gysels et al, 2004a, 2004b; Larmuseau et al, 2009; Mejri et al, 2009, 2011; Boissin et al, 2011; Tougard et al, 2014)

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