High gene flow promotes the genetic homogeneity of the fish goby Pomatoschistus marmoratus (Risso, 1810) from Mar Menor coastal lagoon and adjacent marine waters (Spain)

Abstract

The extreme environmental variability of coastal lagoons suggests that physical and ecological factors could contribute to the genetic divergence among populations occurring in lagoon and open‐coast environments. In this study we analysed the genetic variability of lagoon and marine samples of the sand goby, Pomatoschistus marmoratus (Risso, 1810) (Pisces: Gobiidae), on the SW Spain coast. A fragment of mitochondrial DNA control region (570 bp) was sequenced for 196 individuals collected in five localities: Lo Pagan, Los Urrutias and Playa Honda (Mar Menor coastal lagoon), and Veneziola and Mazarrón (Mediterranean Sea). The total haplotype diversity was h = 0.9424 ± 0.0229, and the total nucleotide diversity was π = 0.0108 ± 0.0058. Among‐sample genetic differentiation was not significant and small‐scale patterns in the distribution of haplotypes were not apparent. Gene flow and dispersal‐related life history traits may account for low genetic structure at a small spatial scale. The high genetic diversity found in P. marmoratus increases its potential to adapt to changing conditions of the Mar Menor coastal lagoon.

Environmental variables, habitat discontinuity and life history shaping the genetic structure of Pomatoschistus marmoratus

“…This leads to the expectation that more genetic variability and population differentiation would be detected with nuclear markers (Ruzzante et al 1998). In fact, our microsatellite results supported this expectation, showing higher values of effective population size and lower rates of gene flow in contrast to our previous mitochondrial data ( Vergara-Chen et al 2010a). Therefore, these results corroborate the conclusions of Daemen et al (2001) affirming that cytoplasmic markers provide a record of the historic and recent gene flow in females, while the nuclear markers estimate recent gene flow in both sexes.…”

“…Otherwise, both types of molecular markers indicated variable rates of genetic exchange among lagoonal samples and between coastal lagoon and marine localities although the overall of the pattern was very similar. The parameter H (a function of H e ) based on mitochondrial DNA data suggested values between 0.01 (Playa Honda) and 0.05 (Los Urrutias), while the migration rates showed significant gene flow from Playa Honda to all remaining localities, and restricted flow from Mazarrón to Veneziola (3.52e-11) and from Lo Pagán to Playa Honda (9.36e-14) (Vergara-Chen et al 2010a). Microsatellite data pointed values of effective population size higher than those obtained with the mitochondrial marker, with the lowest (H) value for Los Urrutias and the highest value for Lo Pagán.…”

“…We used as genotype data, the allele frequencies obtained from the microsatellite data and the haplotype frequencies from our previous study with mitochondrial DNA control region sequences (Vergara-Chen et al 2010a). An analysis of molecular variance (AMOVA) (Excoffier et al 1992) was carried out in ARLEQUIN to assess the hierarchical partitioning of genetic variability within and among populations and among lagoon and marine groups.…”

“…Recently, Vergara-Chen et al (2010a) carried out a study about the genetic structure of P. marmoratus considering small spatial scales (\25 km) into Mar Menor coastal lagoon (SE Spain) and between adjacent localities in Mediterranean Sea (\100 km) using mitochondrial DNA sequences (control region). This study found very low population differentiation considering F ST values and high gene flow rates between lagoon and nearby open sea locations.…”

Genetic diversity across geographical scales in marine coastal ecosystems: Holothuria arguinensis a model species

“…Recent studies have tackled the role of the coastal lagoons and estuaries as inducers of genetic differentiation (González-Wangüemert and Pérez-Ruzafa, 2012;González-Wangüemert and Vergara-Chen, 2014;González-Wangüemert et al, 2006González-Wangüemert et al, 2014a;Vergara-Chen et al, 2010a, 2010b, 2013. The existence of these genetic differences between lagoon and marine populations could be the result of the selection acting in the lagoon organisms which could favor some vital adaptations for surviving in these heterogeneous environments González-Wangüemert et al, 2006;Vergara-Chen et al, 2010a).…”