Extensive population subdivision of the cuttlefish Sepia officinalis (Mollusca: Cephalopoda) around the Iberian Peninsula indicated by microsatellite DNA variation

Abstract

The Atlantic Ocean-Mediterranean Sea junction has been proposed as an important phylogeographical area on the basis of concordance in genetic patterns observed at allozyme, mtDNA and microsatellite DNA markers in several marine species. This study presents microsatellite DNA data for a mobile invertebrate species in this area, the cuttlefish Sepia officinalis, allowing comparison of this relatively new class of DNA marker with previous allozyme results, and examination of the relative effects on gene flow of the Strait of Gibraltar and the Almería-Oran oceanographic front. Genetic variation at seven microsatellite loci screened in six samples from NE Atlantic and Mediterranean coasts of the Iberian Peninsula was high (mean Na = 9.6, mean H e = 0.725). Microsatellites detected highly significant subpopul-

Genome‐wide comparisons reveal a clinal species pattern within a holobenthic octopod—the Australian Southern blue‐ringed octopus, Hapalochlaena maculosa (Cephalopoda: Octopodidae)

“…Furthermore, genetic divergence even among adjacent sampling sites in this study was remarkably high compared to studies of other cephalopods (Doubleday et al., 2009; Higgins et al., 2013; Keskin & Atar, 2011; Moreira, Tomás, & Hilsdorf, 2011; Pérez‐Losada et al., 2002; Reichow & Smith, 2001; Shaw et al., 1999; Zheng et al., 2009). These findings suggest that the high levels of observed genetic divergence among sampling sites are a result of this holobenthic species having insufficient gene flow among populations to counteract the strong effects of random drift, thereby creating a genetic IBD pattern along southwestern and southern coasts of the Australian continent.…”

“…Within sample sites, levels of both observed and expected heterozygosity were quite low compared to other genetic studies in cephalopods (Higgins et al., 2013; Kassahn et al., 2003; Moreira et al., 2011; Pérez‐Losada et al., 2002; Reichow & Smith, 2001; Shaw et al., 1999; Zheng et al., 2009). In part, this is due to differences in estimating heterozygosity between SNP and microsatellite markers, which were used in the above studies (see Vignal, Milan, SanCristobal, & Eggen, 2002), as well as the near impossibility of being able to eliminate all null alleles from the SNP library (Andrews et al., 2016; DaCosta & Sorenson, 2014).…”

“…The observed F st values among sample sites were very high compared to all comparable studies of population divergence in cephalopods (Doubleday et al., 2009; Higgins et al., 2013; Keskin & Atar, 2011; Moreira et al., 2011; Pérez‐Losada et al., 2002; Reichow & Smith, 2001; Shaw et al., 1999; Zheng et al., 2009). Additionally, F st values increased proportionally with geographic distance, implicating an IBD pattern for gene flow, consistent with O. pallidus (Higgins et al., 2013), several species of cuttlefish (Kassahn et al., 2003; Pérez‐Losada et al., 2002), and many terrestrial animals (Wright, 1943).…”

“…Additionally, F st values increased proportionally with geographic distance, implicating an IBD pattern for gene flow, consistent with O. pallidus (Higgins et al., 2013), several species of cuttlefish (Kassahn et al., 2003; Pérez‐Losada et al., 2002), and many terrestrial animals (Wright, 1943). This pattern strongly indicates that populations of the H. maculosa group are finely structured over distance due to their lack of a planktonic dispersal phase.…”

“…These findings strongly indicate that H. maculosa and the WBRO form a single clinal species, following a genetic IBD pattern, common to terrestrial animal taxa (Wright, 1943) and other marine organisms that lack a planktonic life history phase (Barbosa, Klanten, Puritz, Toonen, & Byrne, 2013; Higgins et al., 2013; Kassahn et al., 2003; Pérez‐Losada et al., 2002). There was evidence of strong genetic divergence among sampling sites along the H. maculosa group distribution, most likely due to the limited dispersal capacity and short 2‐month life cycle of the species.…”