Mar Biol (2012) 159:499–505 DOI 10.1007/s00227-011-1830-4 ORIGINAL PAPER Phylogeography of the sub-Antarctic notothenioid Wsh Eleginops maclovinus: evidence of population expansion Santiago Guillermo Ceballos · Enrique Pablo Lessa · Mariela Fernanda Victorio · Daniel Alfredo Fernández Received: 8 June 2011 / Accepted: 20 October 2011 / Published online: 16 November 2011 © Springer-Verlag 2011 Abstract Phylogeography studies add insights into the Introduction geographic and evolutionary processes that underline the genetic divergence of populations. This work examines the Eleginops maclovinus (Cuvier and Valenciennes 1830), geographic genetic structure of the Patagonian blennie, Ele- known as róbalo in Argentina and Chile, is a notothenioid ginops maclovinus, a notothenioid (Perciformes) endemic Wsh (Perciformes) of the monotypic family Eleginopidae. to South American temperate and sub-Antarctic waters, This marine Wsh is endemic to the coastal temperate and using mitochondrial DNA cytochrome b sequences. We sub-Antarctic waters of South America with a range along found 58 haplotypes in the analysis of 261 individual the Atlantic and PaciWc Patagonian coasts from Valparaiso, sequences of 833 base pairs in length. Among-population Chile (33°S) (Pequeño 1989) to San Matias Gulf, Argentina variance was very low (1.62%) and many haplotypes were (40°S) (Cousseau and Perrotta 2000). This eurithermic and shared between several populations across the species geo- euryhaline species that has been described as a protandrous graphic range. Genetic diVerentiation was not consistent hermaphrodite (Calvo et al. 1992; Brickle et al. 2005; with a simple model of isolation by distance, possibly sug- Licandeo et al. 2006) inhabits costal waters, river mouths gesting a lack of equilibrium between gene Xow and local and estuaries (Gosztonyi 1980). On the Patagonian coast, E. genetic drift. The analysis of mismatch distributions, neu- maclovinus is a common Wsh species and an important trality tests, and the Bayesian Skyline Plot showed a pattern component of many trophic webs, both as prey (Goodall consistent with a recent population expansion event that and Galeazzi 1985) and as predator, feeding mainly on ben- may have taken place during the Middle Pleistocene. thic invertebrates such as crustaceans and polychaetes, but also on algae and Wshes (Isla and San Román 1995; Lican- deo et al. 2006; Martin and Bastida 2008; Pequeño et al. 2010). Additionally, E. maclovinus is important for the rec- reational and small food Wsheries throughout much of its Communicated by M. I. Taylor. distribution. Despite its ecological and socioeconomic importance, there is no information regarding its population Electronic supplementary material The online version of this dynamics and genetic structure, which must be understood article (doi:10.1007/s00227-011-1830-4) contains supplementary material, which is available to authorized users. for proper conservation and management. Many ecological and evolutionary features make S. G. Ceballos (&) · M. F. Victorio · D. A. Fernández E. maclovinus an interesting species for a phylogeographic W Centro Austral de Investigaciones Cientí cas (CADIC), study. First, it is an ideal organism to study population Bernardo A. Houssay 200, cp 9410, Ushuaia, Tierra del Fuego, Argentina responses to environmental variation associated with a e-mail: [email protected] broad latitudinal range. Second, E. maclovinus is consid- ered the sister group of the Antarctic notothenioids Wshes E. P. Lessa (Near and Cheng 2008) that dominate the cold shelf waters Sección Evolución, Facultad de Ciencias, Universidad de la República, 4225 Iguá, of Antarctica (Eastman 2005) and provide a classic exam- Montevideo, Uruguay ple of radiation in the absence of competition from most 123 500 Mar Biol (2012) 159:499–505 other Wsh groups (Clarke and Johnston 1996; Eastman 2000). Therefore, this species likely presents several ances- tral traits of the notothenioid radiation (Eastman and Lan- noo 2008). And third, the continental shelf area where E. maclovinus is distributed nowadays was largely aVected by Quaternary glacial cycles. Events such as ice sheet calving into the ocean, retraction of the sea coast line and decrease in marine water temperature during glacial periods (Clapp- erton 1993; Rabassa 2008) might have aVected the habitat suitable for E. maclovinus and thus the population size and geographical structure. Demographic changes may leave genetics footprints in populations (Avise 2000) that can, therefore, be linked to climatic cycles. There are a growing number of studies that associate historical demography with climate changes in a variety of organisms from Pata- gonia such as grasses species (Jakob et al. 2009), rodents (Lessa et al. 2010), fresh water Wshes (Ruzzante et al. 2008; Zemlak et al. 2010) and crabs (Xu et al. 2009). A popula- tion genetic study of E. maclovinus would be an interesting contribution in order to generate an integrated scenario of how the biota has responded to historical climates changes in the entire Patagonian region. To our knowledge, there are no phylogeographic studies on a single marine Wsh species along both Atlantic and PaciWc Patagonian coasts. In this work, we report the Wrst data on population genetics of E. maclovinus along its dis- tributional range using mitochondrial DNA (mtDNA) sequences. Fig. 1 E. maclovinus were collected at nine sites (triangles) along the coast of Patagonia, South America. The approximated range distribu- tion of the species is represented in the map by the shadow coastal area. Materials and methods Abbreviations: San Antonio Oeste (SAO) Sample collection gene were ampliWed by polymerase chain reaction (PCR) from 261 individuals (21–36 per sampling site; Table 1). E. maclovinus individuals (N = 261) were captured using The PCRs used the forward primer MVZ 05 5Ј-CGA trammel nets and gill nets at nine sites along the latitudinal AGC TTG ATA TGA AAA ACC ATC GTT-3Ј (Smith range on the Atlantic and PaciWc Patagonian coasts: San and Patton 1991) and the reverse primer R1negra 5Ј-CCA Antonio Oeste (SAO) (40°50ЈS, 65°04ЈW), Puerto Madryn GTA CTC CTC CAA GTT TGT CGG GG-3Ј, designed (42°46ЈS, 65°01ЈW), Rada Tilly (45°56ЈS, 67°32ЈW) from the alignments of notothenioid cytb sequences. Puerto San Julián (49°19ЈS, 67°42ЈW), Punta María Thirty L of PCR reaction mixtures contained 15 L of (53°57ЈS, 67°26ЈW), Canal Beagle (54°49ЈS 68°10ЈW), total DNA (4 g/mL), 1 unit of Taq DNA polymerase Puerto Aysén (45°22ЈS, 72°51ЈW) Puerto Montt (41°32ЈS, (Promega), 1 £ Taq polymerase buVer, dNTPs (0.2 mM 72°54ЈW) and Concepción (36°44ЈS, 73°11ЈW) (Fig. 1). of each), forward and reverse primers (0.3 mM of each) Muscle samples were collected from each individual and and MgCl2 (2.5 mM). PCR used the following cycling preserved in 99% ethanol. conditions: an initial denaturation of 3 min at 94°C, 30 cycles of 30 s of denaturation at 94°C, 30 s of annealing at DNA extraction, PCR ampliWcation, and sequencing 50°C, and 1 min of extension at 72°C, and a Wnal exten- sion of 5min at 72°C. PCRs were performed in a 2720 Total DNA extractions were performed with sodium dode- Thermal Cycler (Applied Biosystems). PCR products cyl sulfate (SDS)-proteinase K-NaCl-alcohol precipitation were sequenced at Macrogen Korea with both PCR prim- (modiWed from Miller et al. 1988). Approximately 900 base ers. Chromatograms were scored and analyzed using Bio- pairs of the 3Ј end of the mitochondrial cytochrome b (cytb) Edit (Hall 1999). 123 Mar Biol (2012) 159:499–505 501 Table 1 Genetic variation at each site Beast v1.6.0. The run consisted of 100 million generations sampled every 1,000 generations under the HKY + G Population nSNo. sin kH model. Samples before the convergence zone were dis- SAO 25 16 3 10 0.90 0.0047 carded. Pto. Madryn 27 23 1 16 0.96 0.0054 Arlequin 3.11 was used to Wt the spatial expansion Rada Tilly 251510 120.890.0026 model (Schneider and ExcoYer 1999; ExcoYer 2004), to Pto. San Julián 24 20 15 9 0.86 0.0035 estimate the relative timing of expansion. Pta. María 38 20 7 11 0.87 0.0036 Canal Beagle 36 23 14 16 0.88 0.0038 Pto. Aysén 31 21 10 16 0.91 0.0042 Results Pto. Montt 28 23 17 14 0.87 0.0039 Concepción 27 15 9 13 0.90 0.0032 Variation among cytochrome b haplotypes All pop. 261 65 28 58 0.90 0.0039 The Wnal data set consisted of 261 cytb sequences of 833 bp n, sample sizes; S, number of polymorphic sites; No. sin number of sin- gletons, k, number of haplotypes, H, haplotype diversity; and , nucle- in length. An alignment of these sequences showed 65 vari- otide diversity able sites, including 28 singletons and 37 parsimony-infor- mative sites, which deWned 58 haplotypes (GenBank accession numbers JN010371, JN010428; Table 1; Online Data analysis Resource 1). Eight of the 65 variables sites were non-synon- ymous changes that occurred in one (6), two (1) or three (1) The number of haplotypes, the number of polymorphic sites individuals. Haplotype diversity was 0.90 for all individuals and molecular diversity indices for cytb haplotypes, such as and ranged from 0.82 to 0.96 across sites. Nucleotide diver- haplotype diversity (H) and nucleotide diversity (), analy- sity was 0.0039 for all individuals and ranged from 0.0026 to sis of molecular variance (AMOVA), pairwise FST values, 0.0054 across sites. The majority (28) of unique haplotypes W Mantel test, and Tajima’s D and Fu’s FS tests of neutrality (32) were de ned by single nucleotide changes. were calculated in Arlequin 3.11 (ExcoYer et al. 2005). Observed and expected mismatch distributions under an Geographic genetic variation exponential growth population model were obtained using DNAsp V5.1(Librado and Rozas 2009). A minimum span- No Wxed diVerences were observed between populations, ning tree of the haplotypes was generated using the median- and many haplotypes were shared between several popula- joining method (Bandelt et al.