Phylogenetic approaches to delimit genetic lineages of the Mytilus complex of South America: how many species are there?
KEY WORDS: mussel, Mytilus, Mytilus edulis complex, South America, COI, 16S
The genus Mytilus, as defined by Linnaeus (1758), consists of two types of species: Those that are hard-shelled for which two species, Mytilus californianus and Mytilus coruscus, have been defined; and those that are smooth-shelled for which three species, Mytilus edulis, Mytilus galloprovincialis, and Mytilus trossulus, have been recognized. Despite this, over the past decade or so, there has been an extensive debate about the species definitions of the latter group of Mytilus species. This debate has arisen mainly due to three factors: (1) the great morphological and morphometric similarity of the valves (McDonald et al. 1991) of smooth-shelled species; (2) the ability of these species to interbreed and produce viable hybrid offspring, and (3) the great genetic similarity or unclear genetic patterns seen among the smooth-shelled species.
Furthermore, cross breeding experiments have been conducted and viable hybrids were successfully produced both in controlled (Toro et al. 2012) and natural environments (McDonald & Koehn 1988, Inoue et al. 1995, Wilhelm & Hilbish 1998, Rawson et al. 1999, Brannock et al. 2009, Westfall & Gardner 2010, Larrain et al. 2012, Toro et al. 2012, Lourenco et al. 2015). In addition to this, phenotypic studies have shown that smooth-shelled Mytilus are highly plastic such that the valve morphology is largely determined by the organism's local environment (McDonald et al. 1991).
Because of this lack of clarity in morphological identification, smooth-shelled Mytilus have been grouped into a species complex, or the Mytilus edulis complex. Within the definition of this complex, the species should have a common evolutionary ancestor or an "edulis type." As it is not known when the three identified species of this complex diverged from the common ancestor, this complex could still be undergoing speciation that would make it very difficult to delimit species (Gosling 1992).
The delimitation of species becomes even more complex when analyzed using the existing information for the groups present in the southern hemisphere because different genetics groups has been found. Taxonomic identification is even more difficult when trying to identify Mytilus species present along the coast of Chile. This is the case because sampling along the coast of Chile has been sparse.
The Mytilus mussel in Chile is of high economic importance because it is produced in large volumes in aquaculture. Chile is now one of the largest mussel producers in the world (FAO 2014), and Chilean Mytilus is one of the top five mollusc species produced in world aquaculture with production of 288,000 tons in 2011 (FAO 2013). The aquaculture production of this resource is sustained entirely from natural populations because the seeds for aquaculture are obtained from the natural environment (Uriarte 2008). For the sustainable aquaculture of this species, it is important to know about the species distinctions and population dynamics of this resource.
Along the Chilean coast, natural beds of Mytilus are found from 38[degrees]S to the southern tip of the country at 54[degrees]S (Toro et al. 2006). This species was initially described as Mytilus chilensis (Hupe, 1854), and the name M. chilensis has been used recurrently in the literature in various areas of research. In fact, more than 150 citations can be found in the ISI web of science using this name for the Chilean mussel species (e.g., Enriquez et al. 1992, Jaramillo et al. 1992, Simpfendorfer et al. 1995, Toro 1998, Labarta et al. 2002, Rego et al. 2002, Velasco & Navarro 2002, Velasco & Navarro 2003, Toro et al. 2004, Krapivka et al. 2007, Ouagajjou et al. 2011, Ibarrola et al. 2012, Larrain et al. 2014, Nunez-Acuiia & Gallardo-Escarate 2014, Oyarzun et al. 2014, Vallejos et al. 2014). The Chilean mussel can also be found under the name Mytilus edulis chilensis (Gray et al. 1997, Gray et al. 1999, Mercado et al. 2005, Arenas et al. 2006, Duarte et al. 2011), and recently as Mytilus edulis platensis (Borsa et al. 2012, Diaz & Campos 2014). The name M. edulis platensis was derived for the Mytilus species that inhabits the coast of Argentina.
Many genetic studies of smooth-shelled Mytilus have been conducted, and some of these have used allozymes (McDonald et al. 1991, Carcamo et al. 2005, Toro et al. 2006), nuclear markers (Daguin & Borsa 2000, Wood et al. 2003, Westfall & Gardner 2010), restriction fragment length polymorphism (RFLP) (Westfall et al. 2010), mitochondrial DNA (Hilbish et al. 2000, Gerard et al. 2008), or microsatellites (Ouagajjou et al. 2011). Specifically, the evolutionary and phylogenetic relationships within the Mytilus group have been analyzed using high-resolution markers and DNA sequencing. This work has mainly been done by Hilbish et al. (2000) and Gerard et al. (2008). One study by Hilbish et al. (2000) aimed to determine that Mytilus origin location or migration route could have led to the antitropical distribution exhibited by the genus. In this study, 47 Mytilus samples from both hemispheres were analyzed using RFLP analysis. The results of the study indicate the existence of two migration events from the northern to the southern hemisphere, both via an Atlantic route. Occurring in the Pleistocene, one of these events is considered to be ancient whereas the other migration event is thought to have occurred more recently. Following this, another study, employing a greater sampling effort and using Cytochrome oxidase I (COI) gene sequences, reassessed the time of divergence of Mytilus species (Gerard et al. 2008). This study was conducted to define the times at which the Mytilus genus split and colonized the southern hemisphere. By analyzing 171 COI sequences COI and 224 16S RNA ribosomal subunit (16S) sequences, this study detected genetic population differentiation between the hemispheres. Specifically, populations from southern Chile, Kerguelen, Tasmania, and New Zealand were found to be different and were found to have diverged from the northern clade between 0.5 and 1.3 million years ago. Following these results, the northern clade of Mytilus consists of populations found in the northern hemisphere, Western Australia, South Africa, and northern Chile (Dichato).
More recently, results gathered from RFLP and nuclear gene polymorphism data have indicated the presence of Mytilus trossulus, Mytilus galloprovincialis, and possible hybrids in Chile. Both M. trossulus and M. galloprovincialis were found off the coast of the Bio-Bio Region of Chile, however the Mytilus hybrids were found in regions where Chilean mussels are farmed (Larrain et al. 2012). Further to this, results of a detailed review also indicate that Mytilus is genetically distinct in the two hemispheres (Borsa et al. 2012). Also, this review shows that Chilean Mytilus are different from northern hemisphere Mytilus. Because of this, Chilean Mytilus should be identified as Mytilus edulis platensis following taxonomic priority rules.
Based on the results of previous work, the study here in presented attempts to determine if the phylogenetic patterns found by Hilbish et al. (2000) and Gerard et al. (2008) are present in this system (South America). The study emphasizes the Chilean coast, adding information from the southern cone of South America. Furthermore, here the possible presence of Mytilus trossulus and its hybrids in Chile is assessed. Finally, a taxonomically suitable identification of the Mytilus species present in Chile is proposed.
MATERIALS AND METHODS
Samples of Mytilus were collected from eight locations along the coast of Chile (see Table 1 for details). Of these, samples from Tumbes (TUM) were determined to be Mytilus galloprovincialis (Toro et al. 2006, Astorga 2012, Tarifeno et al. 2012) and samples from the other seven locations were determined to be Mytilus edulis platensis (Table 1). In addition, samples from two other locations in the southern cone of South America were analyzed. These locations included Montevideo, Uruguay and Puerto Deseado, Argentina. All of the samples from the southern cone of Southern America-Chile. Argentina, and Uruguay--excluding TUM, will be called Mytilus from South America.
Deoxyribose nucleic acid was only extracted from the mantle of female mussels using a mollusc extraction kit (E.Z. N.A.) following the manufacturer's instructions. The COI mitochondrial gene was amplified using the HCO and LCO universal primers (Folmer et al. 1994). The 16S RNA ribosomal subunit (16S) was amplified using the 16SAR and 16SBR primers (Palumbi et al. 1991). The sequences were edited and aligned utilizing the BIOEDIT 5.0.9 program (Hall 1999).
In total, 426 COI sequences and 190 16S sequences of different Mytilus species were compared; the sequences came from samples that encompass a worldwide distribution. Of the 426 COI sequences analyzed, 127 were newly generated for this study and 299 were obtained from the National Center for Biotechnology Information database (www.ncbi.nlm.nih.gov). In addition, of the 190 16S sequences analyzed in this study, 93 were originally sequenced, and 97 were mined from National Center for Biotechnology Information (details in Table 1 and Fig. 1).
Standard genetic diversity indices including the number of segregating sites (S), the number of haplotypes (h), haplotype diversity, nucleotide diversity ([pi]), and the mean number of pairwise differences ([pi]) were estimated for each group and gene, using DnaSP v5.00.04 (Librado & Rozas 2009). The software MEGA 6.0 (Tamura et al. 2013) was used to estimate genetic divergence between samples using the number of base substitutions per site and by averaging over all of the sequence pairs between groups. The significance and SE of the values were evaluated by 1000 bootstrap replicates. Moreover, the percentage of different nucleotides was measured using DnaSP v5.00.04 (Librado & Rozas 2009). To perform this analysis, the groups were separated following the criteria of Gerard et al. (2008) where haplotypes in the northern hemisphere and southern hemisphere are defined for galloprovincialis.
Because the 16S gene is commonly used to build marine invertebrate phylogenies and to identify operational taxonomic units and species (for example de Luna Sales et al. 2013, Pulliandre et al. 2014), this gene was used for the phylogenetic analyses. Maximum Likelihood reconstructions were performed using the best substitution model, as is implemented in the software MEGA 6.0 (Tamura et al. 2013). Bayesian inference method (BI) was performed using the software Mr. Bayes (Huelsenbeck & Ronquist 2001). The evolutionary model was chosen according to the BIC Model Selection as implemented in Modeltest 3.7 (Posada & Crandall 1998). Posterior probabilities were estimated over 10,000,000 generations via one run of four simultaneous Markov Chain Monte Carlo chains with every 1,000th tree saved. The first 10% burn-in was discarded following suggestions by Felsenstein (1985). In the phylogenies, 16S sequences of Mytilus californianus and Mytilus coruscus were chosen as out-groups (Gerard et al. 2008).
The COI gene is a commonly used marker for phylogeo-graphic studies. This molecular marker can be used to determine the number of species and the relationships among haplotypes (for example Cardenas et al. 2009, Haye et al. 2014). The relationships among the observed haplotypes in this study were assessed by constructing median joining networks (Bandelt et al. 1999) using the software Network v4.613 (www.fluxus-engineering. com). To determine connections in the network, a star contraction procedure was applied before network calculation was performed (Forster et al. 1996). After calculating the network, maximum parsimony analysis was used to filter out uninformative branches (Polzin & Daneshmand 2003). Two different analyses were performed: first, the number of shared haplotypes and the distribution of haplotypes among species were visualized by building a network with the entire dataset including all of the analyzed species. Here a total of 426 COI sequences each having at least 399 bp were used to build the network. The second analysis was performed exclusively with samples from South America. The aim of this analysis was to identify the spatial pattern of the haplotype distribution. For this second analysis, a database composed of sequences of 127 individuals was used and each sequence used was 667 bp in length.
The genetic diversity indices calculated for the smooth-shelled species of Mytilus showed the same uniform diversity distribution regardless of the gene analyzed (Table 2 for COI and Table 3 for 16S). Between pairs of groups (species), there was low genetic divergence, again regardless of the gene tested. Despite this, slight differentiation was observed between northern hemisphere Mytilus galloprovincialis [with northen haplotype (NH)] and Mytilus edulis using the COI gene. It should be noted that differentiation was observed between the two groups of M. galloprovincialis [NH with southern haplotype (SH)]; and within the same hemisphere the groups were more similar to each than to those from the other hemisphere (M. edulis with M. galloprovincialis from the northern hemisphere, and Mytilus from South America with M. galloprovincialis from southern hemisphere) (Table 4 for COI gene). The genetic divergence based on the 16S data showed a similar pattern to that observed for the COI gene (Table 5 for 16S). In both datasets, the smallest divergence observed was between the samples of Mytilus from South America and the M. galloprovincialis samples that have the SH. The level of genetic differentiation between Mytilus from South America and the M. galloprovincialis-SH was 1.91% based on the COI gene and 0.27% based on the 16S gene. The divergence between Mytilus from South America and the M. galloprovincialis-NH was 1.73% for the COI gene and 1.57% for the 16S gene. For the comparison between Mytilus from South America and M. edulis, the value was 1.86% based on the COI gene and 1.13% based on 16S. The percent divergence between M. galloprovincialis-SH and M. edulis is 2.20% for the COI gene and 2.45% for 16S. Between M. galloprovincialis-NH and M. edulis, 1.05% and 2.67% divergence was found for COI and 16S, respectively. Finally, the percentage of different nucleotides between M. galloprovincialis-SH and -NH was 2.40% based on the COI gene and 2.53% based on 16S.
Phylogenetic reconstruction with the 16S gene showed a similar topology independent of whether the maximum likelihood (ML) or BI analysis method was used (Fig. 2). In this reconstruction, three well-supported clades were detected. The first clade was composed of samples of Mytilus edulis, Mytilus galloprovincialis-NH, one sample of M. galloprovincialis-SH, and samples from TUM (Chile) in South America. The second clade is composed of samples of M. edulis, M. galloprovincialis-NH, and Mytilus trossulus with only one South America sample coming from Uruguay. The third clade is composed of samples of M. galloprovinciales-NH and -SH, M. edulis, and samples from South America collected in TUM (Chile). The sequences of other samples from South America and samples of M. galloprovincialis-SH clustered into a large polytomy indicating considerable uncertainty in the relationship among these taxa.
The network analysis using the whole dataset, i.e., including samples from Mytilus edulis, Mytilus trossulus, Mytilus galloprovincialis-NH, M. galloprovincialis-SH and Mytilus from South America, is shown in Figure 3. The network indicates the existence of two haplotypes of high frequency separated by six mutational steps. One of these haplotypes was observed in a total of 114 individuals including samples from M. edulis, M. galloprovincialis-NH, and in several South America and M. galloprovincialis-SH samples. Several other lower frequency haplotypes are connected to the one large haplotype previously described. These haplotypes are separated by a distance of one mutational step and are mainly from the M. galloprovincialis-NH and M. edulis samples. Other high frequency haplotypes were found in 69 samples. These were mainly found in samples from South America, but there were also some detected in the M. galloprovincialis-SH and -NH samples. In addition, the M. trossulus haplotypes were independent from the main network; these haplotypes were separated from the main network by 34 mutational steps.
When samples of Mytilus from South America were analyzed (Fig. 4), one central high frequency haplotype was observed in a total of 28 individuals from Puerto Saavedra. Queule, Chaihuin, Yaldad, Puerto Balmaceda; Punta Arenas, and Puerto Deseado. In addition, several other haplotypes were detected; these included individuals from several sites with no apparent spatial segregation of the genetic diversity. This suggests that there is no spatial structure to Mytilus populations in South America. However, exceptions to this include three haplotypes from ARG that are nine mutational steps away from the rest of the network.
This study supports the hypothesis proposed by Hilbish et al. (2000) and Gerard et al. (2008) as two main groups of Mytilus galloprovincialis were found. In addition, a clear separation of Mytilus trossulus and other Mytilus species was found. Further to this, there is no evidence of the presence of this species or hybrids in Chile. Finally, there is evidence that South America samples are taxonomically independent. This also suggests that there has been a recent introduction of M. galloprovincialis-NH in TUM and ARG.
The results herein presented confirm the low phylogenetic divergence between groups within the Mytilus edulis complex, in comparison, with the other Mytilus species. The low genetic diversity within the M. edulis complex is to be expected, as it is known that these species interbreed (Beaumont et al. 2004, Beaumont et al. 2008, Gosling et al. 2008, Klibansky & McCartney 2014, Lourenco et al. 2015) and have few distinct morphological characteristics (Daguin & Borsa 1999, Oyarzun et al. 2014). Despite this, when the genetic and phylogenetic divergences of this species complex are analyzed in detail, differentiation can be found. Phylogenetic analysis of the COI gene sequence data shows a separation of the northern hemisphere samples from the southern hemisphere samples. This generates a clade of northern haplotypes plus some groups present in the southern hemisphere. This clade includes samples from South Africa, Western Australia, and TUM on the coast of Chile. It is possible that this may have resulted from a more recent introduction (Branch & Stefanni 2004, Braby & Somero 2005, Robinson et al. 2007, Lockwood & Somero 2011). The presence of Mytilus galloprovincialis in TUM has been reported to be a recent introduction of galloprovincialis (Branch & Stefanni 2004, Castilla & Neill 2009). Therefore, this recent introduction may also have resulted from the second trans-equatorial migration from the northern hemisphere as proposed by Hilbish et al. (2000).
This separation of haplotypes into clusters associated with the hemispheres has already been detected by Gerard et al. (2008). This study demonstrates that there are great differences between southern hemisphere Mytilus samples. This is confirmed in the present work by the high genetic variability seen in the galloprovincialis-SH samples. The greatest number of different nucleotides was found within this group (Table 2).
The results herein presented indicate that there is little genetic differentiation between species of the Mytilus edulis complex. In general, a greater similarity was observed between M. edulis and Mytilus galloprovincialis from the northern hemisphere than between Mytilus from South America and edulis.
Using both markers, phylogenetic analyses of the South American samples show a separation of the data into a single clade with low genetic differentiation within this clade. These samples also form a group with the Kerguelen samples, as was also detected by Gerard et al. (2008). It is possible that South American Mytilus are more genetically distinct from the Mytilus edulis group (1.5%) and from the northern hemisphere galloprovincialis (1.7%) than they are from the southern hemisphere galloprovincialis (1.0%). The divergence between Mytilus of the northern and southern hemispheres has been estimated as 1.4% (Hilbish et al. 2000). Interestingly, this is the same as that observed in this study if the average of the divergence rate of galloprovincialis from the southern hemisphere and that of Mytilus from South America (1.4%) is considered; The other study measuring divergence rates also considered these together (Hilbish et al. 2000). It is possible that due to Atlantic transequatorial colonization, these new southern hemisphere groups have undergone local differentiation. This differentiation would have created at least two groups including one in South America and another in the southwest Pacific encompassing New Zealand, Tasmania, and eastern Australia. This group in the south hemisphere may in turn be structured, as shown by Gerard et al. (2008, 2015). Finally, as a result of more recent migration (Hilbish et al. 2000), there is likely a group consisting of northern haplotypes. This would include the groups of South Africa and Western Australia. The divergence results would suggest an absence of gene flow between the hemispheres and potential differentiation through local adaptation. This is in contrast with the situation between Mytilus galloprovincialis and M. edulis observed in the northern hemisphere where introgression and some degree of gene flow have been reported (Quesada et al. 1998. Bierne et al. 2002). Based on the analysis of the sperm ultrastructure of the South American samples (i.e. Mytilus chilensis) and M. galloprovincialis samples from the Chilean coast, differences have been found which corroborate the current differentiation between these groups. From this, it is thought that sperm ultrastructures could be used as characteristics for taxonomic identification (Oyarzun et al. 2014). This being said, spermatozoa differentiation has not prevented reciprocal reproduction between samples of South America and M. galloprovincialis (Toro et al. 2012). These results indicate that there is greater differentiation of Mytilus between the hemispheres than between the classic species. Furthermore, Mytilus from South America are consistently different from edulis and galloprovincialis.
Thus, to return to the three initial questions, the following conclusions are made. First, the hypotheses of Hilbish et al. (2000) and Gerard et al. (2008) could be corroborated with exhaustive sampling of the coast of the southern cone of South America. Second, no trossulus haplotypes were detected among the South American samples. Because the level of divergence within this group has been shown to be very high, one would have expected to detect this species rapidly. Therefore, the presence of trossulus and its hybrids along the Chilean coast is discounted in contrast to that reported by Larrain et al. (2012). Finally, the taxonomic status of the group present along the coast of South America cannot be easily defined.
Based on the results presented, Mytilus from South America are genetically distinct from edulis. It is possible then that South American Mytilus should not be considered as a subspecies of Mytilus edulis as it has recently been called (M. edulis platensis). Instead, this group should be treated as a differentiated cluster based on its high divergence from the edulis group. If however, the proposal of the edulis complex is put forth, all the species identified to date would be subspecies of this group including M. edulis edulis; M. edulis galloprovincialis, M. edulis planulatus and M. edulis platensis. This is not feasible. Considering the great divergence between the two haplotypes of galloprovincialis, which is greater than their divergence from edulis, a different identification scheme is proposed. The following is suggested: M. edulis should be the name for species from the northern hemisphere; Mytilus galloprovincialis should be the name used for species from the northern hemisphere and for the exceptions present in the southern hemisphere. In the southern hemisphere, Mytilus planulatus should be the named used for specimens from South America, Kerguelen, and the southwest Pacific (eastern Australia, Tasmania and New Zealand); or perhaps two differentiated groups should exist for the southern hemisphere, namely planulatus and plalensis. Borsa et al. (2012) proposed this later identification schemed based on the analysis of the literature existing at the date of their work. Following the rules of taxonomic priority, the name frequently used in the literature for samples from the Chilean coast (Mytilus chilensis) would cease to be used.
We thank Project Fondecyt 1130716, to the Millennium Nucleus Center for the Study of Multiple drivers on Marine Socio-Ecological Systems (MUSELS) by MINECON Project NC120086. We also thank Dr. Jorge Toro, who collected some of the samples for this study.
Arenas, G., S. H. Marshall, V. Espinoza. I. Ramirez & H. Pena-Cortes. 2006. Protective effect of an antimicrobial peptide from Mytilus edulis chilensis expressed in Nicoliana tabacum. L. Electronic. J. Biotechnol. 9:144-151.
Astorga. M. 2012. Estado actual de la genetica de poblaciones del chorito Mytilus chilensis en las costas chilenas. In: Astorga, M. P., J. Toro & V. Martinez, editors. Genetica de Mitilidos y su impacto en la mitilicultura. Chile: Editorial Universidad Austral de Chile & Encubierta Editores, pp. 20-25.
Bandelt, H., P. Forster & A. Rohl. 1999. Median-joining networks for inferring intraspecific phylogenies. Mot. Biol. Evol. 16:37-48.
Beaumont, A., G. Turner, A. Wood & D. Skibinski. 2004. Hybridisations between Mytilus edulis and Mytilus galloprovincialis and performance of pure species and hybrid veliger larvae at different temperatures. J. Exp. Mar. Biol. Ecol. 302:177-188.
Beaumont. A., M. Hawkins, F. Doig, 1. Davies & M. Snow. 2008. Three species of Mytilus and their hybrids identified in a Scottish Loch: natives, relicts and invaders? J. Exp. Mar. Biol. Ecol. 367:100-110.
Bierne, N., P. David, P. Boudry & F. Bonhomme. 2002. Assortative fertilization and selection at larval stage in the mussels Mytilus edulis and M. galloprovincialis. Evolution 56:292-298.
Borsa, P., V. Rolland & C. Daguin-Thiebaut. 2012. Genetics and taxonomy of Chilean smooth-shelled mussels, Mytilus spp. (Bivalvia: Mytilidae). C. R. Biol. 335:51-61.
Branch, G. & C. Steffani. 2004. Can we predict the effects of alien species? A case-history of the invasion of South Africa by Mytilus galloprovincialis (Lamarck). J. Exp. Mar. Biol. Ecol. 300:189-215.
Brannock, P., D. Wethey & T. Hilbish. 2009. Extensive hybridization with minimal introgression in Mytilus galloprovincialis and M. trossulus in Hokkaido, Japan. Mar. Ecol. Prog. Ser. 383:161-171.
Brannock, P., M. Roberts & T. Hilbish. 2013. Ubiquitous heteroplasmy in Mytilus spp. resulting from disruption in doubly uniparental inheritance regulation. Mar. Ecol. Prog. Ser. 480:131-143.
Braby, C. & G. Somero. 2005. Ecological gradients and relative abundance of native and invasive blue mussels in the California hybrid zone. Mar. Biol. 6:1249-1262.
Cao, L., E. Kenchington, E. Zouros & G. C. Rodakis. 2004. Evidence that the large noncoding sequence is the main control region of maternally and paternally transmitted mitochondrial genomes of the marine mussel (Mytilus spp.). Genetics 167:835-850.
Cao, L., B. S. Ort, A. Mizi, G. Pogson, E. Kenchington. E. Zouros & G. C. Rodakis. 2009. The control region of maternally and paternally inherited mitochondrial genomes of three species of the sea mussel genus Mytilus. Genetics 181:1045-1056.
Cardenas, L., J. C. Castilla & F. Viard. 2009. A phylogeographical analysis across three biogeographical provinces of the south-eastern Pacific: the case of the marine gastropod Concholepas concholepas. J Biogeogr. 36:969-981.
Castilla. J. & P. Neill. 2009. Marine bioinvasions in the southeastern Pacific: status, ecology, economic impacts, conservation and management. In: Biological invasions in marine ecosystems. Berlin. Heidelberg: Springer, pp. 439-457.
Carcamo, C., A. Comesana, F. Winkler & A. Sanjuan. 2005. Allozyme identification of mussels (Bivalvia: Mytilus) on the Pacific coast of South America. J. Shellfish Res. 24:1101-1115.
Daguin. C. & P. Borsa. 2000. Genetic relationships of Mytilus galloprovincialis Lmk. Populations worldwide: evidence from nuclear-DNA markers. Geol. Soc. Lond. Spec. Publ. 177:389-397.
Daguin, C. & P. Borsa. 1999. Genetic characterisation of Mytilus galloprovincialis Lmk. in North West Africa using nuclear DNA markers. J. Exp. Mar. Biol. Ecol. 235:55-65.
Diaz, P. & B. Campos. 2014. Ontogenia de la concha larval y postlarval de cuatro especies de bivalvos de la costa del Pacifico sureste. Rev. Biol. Mar. Oceanog. 49:175-191.
Duarte, C., E. Giarratano, O. Amin & L. Comoglio. 2011. Heavy metal concentrations and biomarkers of oxidative stress in native mussels (Mytilus edulis chilensis) from Beagle Channel coast (Tierra del Fuego, Argentina). Mar. Pollut. Bull. 62:1895-1904.
Enriquez, R., G. G. Frosner, V. Hochstein-Mintzel, S. Riedemann & G. Reinhardt. 1992. Accumulation and persistence of hepatitis A virus in mussels. J. Med. Virol. 37:174-179.
FAO. 2013. FAO yearbook. Fishery and Aquaculture Statistics (2011). Rome, Italy: FAO. 76 pp.
FAO. 2014. The State of World Fisheries and Aquaculture 2014. Opportunities and challenges. Rome, Italy: FAO. 223 pp.
Felsenstein, J. 1985. Confidence limits on phylogenies: an approach using the bootstrap. Evolution 39:783-791.
Folmer, O., M. Black. W. Hoeh. R. Lutz & R. Vrijenhoek. 1994. DNA primers for amplification of mitochondrial cytochrome c oxidase subunit I from diverse metazoan invertebrates. Mol. Mar. Biol. Bioteclmol. 3:294-299.
Forster, P., R. Harding, A. Torroni & H.J. Bandelt. 1996. Origin and evolution of native American mtDNA variation: a reappraisal Am. J. Hum. Genet. 59:935-945.
Gerard. K., N. Bierne, P. Borsa, A. Chenuil & J. Feral. 2008. Pleistocene separation of mitochondrial lineages of Mytilus spp. mussels from Northern and Southern Hemispheres and strong genetic differentiation among southern populations. Mol. Phylogenet. Evol. 49:84-91.
Gerard, K., C. Roby, N. Bierne, P. Borsa, J. Feral & A. Chenuil. 2015. Does natural selection explain the fine scale genetic structure at the nuclear exon Glu5' in blue mussels from Kerguelen? Ecol. Evol. 5:1456-1473.
Gosling, E., S. Doherty & N. Howley. 2008. Genetic characterization of hybrid mussel (Mytilus) populations on Irish coasts. J. Mar. Biol Ass. U.K. 88:341-346.
Gosling, E. 1992. Systematics and geographic distribution of Mytilus. In: Gosling E. M., editor. The mussel Mytilus: ecology, physiology, genetics and culture. Dev. Aquacult. Fish. Sci. 25. pp. 1-20.
Gray, A., P. I. Lucas, R. Seed & C. A. Richardson. 1999. Mytilus edulis chilensis infested with Coccomyxa parasitica (Chlorococcales, Coccomyxaceae). J. Molluscan Stud. 65:289-294.
Gray, A. P., R. Seed & C. A. Richardson. 1997. Reproduction and growth of Mytilus edulis chilensis from the Falkland Islands. Sci. Mar. 61:39-48.
Hall, T. 1999. BioEdit: a user-friendly biological sequence alignment editor and analysis program for Windows95/98/NT. Nucleic Acids Symp. Ser. 41:95-98.
Haye. P., N. Segovia, N. Munoz-Herrera, F. Galvez, A. Martinez, A. Meynard & S. Faugeron. 2014. Phylogeographic structure in benthic marine invertebrates of the southeast Pacific coast of Chile with differing dispersal potential. PLoS One 9:e88613.
Hilbish, T., A. Mullinax, S. Dolven, A. Meyer, R. Koehn & P. Rawson. 2000. Origin of the antitropical distribution pattern in the marine mussels (Mytilus spp.): routes and timing of transequatorial migration. Mar. Biol. 136:69-77.
Huelsenbeck. J. & F. Ronquist. 2001. MRBAYES: Bayesian inference of phylogenetic trees. Bioinformatics 17:754-755.
Ibarrola. I., U. Arambalza, J. M. Navarro. M. B. Urrutia & E. Navarro. 2012. Allometric relationships in feeding and digestion in the Chilean mytilids Mytilus chilensis (Hupe), Choromytilus chorus (Molina) and Aulacomya ater (Molina): a comparative study. J. Exp. Mar. Biol. Ecol. 426:18-27.
Inoue, K., J. Waite, M. Matsouka, S. Odo & S. Harayama. 1995. Interspecific variations in adhesive protein sequences of Mytilus edulis, M. galloprovincialis, and M. trossulus. Biol. Bull. 189:370-375.
Jaramillo, E., C. Bertran & A. Bravo. 1992. Community structure of the subtidal macroinfauna in an estuarine mussel bed in southern Chile. Mar. Ecol. (Berl.) 13:317-331.
Klibansky, L. & M. McCartney. 2014. Conspecific sperm precedence is a reproductive barrier between free-spawning marine mussels in the northwest Atlantic Mytilus hybrid zone. PLoS One 9:e 108433.
Krapivka, S., J. Toro, A. Alcapan, M. Astorga. P. Presa, M. Perez & R. Guinez. 2007. Shell shape variation along the latitudinal range of the Chilean blue mussel Mytilus chilensis (Hupe 1854). Aquacult. Res. 38:1770-1777.
Labarta, U., M. Fernandez-Reiriz, J. Navarro & A. Velasco. 2002. Enzymatic digestive activity in epifaunal (Mytilus chilensis) and infaunal (Mulinia edulis) bivalves in response to changes in food regimes in a natural environment. Mar. Biol. 140:669-676.
Larrain, M., N. F. Diaz, C. Lamas, C. Vargas & C. Araneda. 2012. Genetic composition of Mytilus species in mussel populations from southern Chile. Lat. Am. J. Aquat, Res. 40:1077-1084.
Larrain. M., N. Diaz, C. Lamas, C. Uribe & C. Araneda. 2014. Traceability of mussel (Mytilus chilensis) in southern Chile using microsatellite molecular markers and assignment algorithms: exploratory survey. Food Res. Int. 62:104-110.
Librado. P. & J. Rozas. 2009. DnaSP v5: a software for comprehensive analysis of DNA polymorphism data. Bioinformatics 25:1451-1452.
Liu. J., Q. Li, L-F. Kong, J. Chen, X. D. Zheng & R. H. Yu. 2011. COI-based DNA barcoding in Mytilidae species (Mollusca: Bivalvia). Acta Hydrobiol. Sin. 35:874-881.
Lockwood. B. & G. Somero. 2011. Invasive and native blue mussels (genus Mytilus) on the California coast: the role of physiology in a biological invasion. J. Exp. Mar. Biol. Ecol. 400:167-174.
Lourenco, C. R., K. R. Nicastro, E. A. Serrao, R. Castilho & G. I. Zardi. 2015. Behind the mask: cryptic genetic diversity of Mytilus galloprovincialis along southern European and northern African shores. J. Mollus. Stud. 81:390-387.
Luna Sales, J., P. Shaw, M. Haimovici, U. Markaida, B. Cunha, J. Ready & I. Sampaio. 2013. New molecular phylogeny of the squids of the family Loliginidae with emphasis on the genus Doryteuthis Naef, 1912: mitochondrial and nuclear sequences indicate the presence of cryptic species in the southern Atlantic Ocean. Mol. Phylogenet. Evol. 68:293-299.
Matsumoto, M. 2003. Phylogenetic analysis of the subclass Pteriomorphia (Bivalvia) from mtDNA COI sequences. Mol. Phylogenet. Evol. 27:429-440.
McDonald, J., R. Seed & R. Koehn. 1991. Allozymes and morphometric characters of three species of Mytilus in the Northern and Southern Hemispheres. Mar. Biol. 111:323-333.
McDonald, J. & R. Koehn. 1988. The mussels Mytilus galloprovincialis and M. trossulus on the Pacific coast of North America. Mar. Biol. 99:111-118.
Mercado, L., P. Schmitt, S. Marshall & G. Arenas. 2005. Gill tissues of the mussel Mytilus edulis chilensis: a new source for antimicrobial peptides. Electron. J. Biotechnol. 8:284-290.
Nunez-Acuna, G. & C. Gallardo-Escarate. 2014. The myostatin gene of Mytilus chilensis evidences a high level of polymorphism and ubiquitous transcript expression. Gene 536:207-212.
Ouaggajou, Y., P. Presa, M. Astorga & M. Perez. 2011. New polymorphic microsatellite markers for the mussel Mytilus edulis chilensis and cross-priming testing in three Mytilus species. J. Shellfish Res. 30:325-330.
Oyarzun, P., J. Toro, O. Garrido, C. Briones & R. Guinez. 2014. Diferencias en la ultraestructura espermatica entre Mytilus chilensis y Mytilus galloprovincialis (Bivalvia, Mytilidae):? Se puede utilizar como un caracter taxonomico? Lat. Am. J. Aquat. Res. 42:172-179.
Palumbi, S., A. Martin, S. Romano, W. McMillan, L. Stice & G. Grabowski. 1991. The simple fool's guide to PCR. Version 2.0. Honolulu. HI: Department of Zoology, University of Hawaii.
Polzin, T. & S. Daneshmand. 2003. On Steiner trees and minimum spanning trees in hypergraphs. Oper. Res. Lett. 31:12-20.
Posada, D. & K. Crandall. 1998. Modeltest: testing the model of DNA substitution. Bioinformatics 14:817-818.
Pulliandre, N., P. Bouchet, T. F. Duda, S. Kauferstein, A. J. Kohn, B. M. Olivera, M. Watkins & C. Meyer. 2014. Molecular phylogeny and evolution of cone snails (Gastropoda, Conidae). Mol. Phylogenet. Evol. 78:290-303.
Quesada, H., M. Warren & D. O. Skibinski. 1998. Nonneutral evolution and differential mutation rate of gender-associated mitochondrial DNA lineages in the marine mussel Mytilus. Genetics 149:1511-1526.
Rawson, P., V. Agrawal & T. Hilbish. 1999. Hybridization between the blue mussels Mytilus galloprovincialis and M. trossulus along the Pacific coast of North America: evidence for limited introgression. Mar. Biol 134:201-211.
Rawson, P. & T. Hilbish. 1995. Distribution of male and female mtDNA lineages in populations of blue mussels, Mytilus trossulus and M. galloprovincialis, along the Pacific coast of North America. Mar. Biol. 124:245-250.
Rego, I., A. Martinez, A. Gonzalez-Tizon, J. Vieites, F. Leira & J. Mendez. 2002. PCR technique for identification of mussel species. J. Agric. FoodChem. 50:1780-1784.
Riginos, C., M. J., Hickerson, C. M. Henzler & C. W. Cunningham. 2004. Differential patterns of male and female mtDNA exchange across the Atlantic Ocean in the blue mussel, Mytilus edulis. Evolution 58:2438-2451.
Riginos, C. & C. M. Henzler. 2008. Patterns of mtDNA diversity in North Atlantic populations of the mussel Mytilus edulis. Mar. Biol. 155:399-412.
Robinson, T., C. Griffiths, G. Branch & A. Govender. 2007. The invasion and subsequent die-off of Mytilus galloprovincialis in Langebaan Lagoon, South Africa: effects on natural communities. Mar. Biol. 152:225-232.
Sharma. P., J. Zardus, E. Boyle, V. Gonzalez, R. Jennings, E. McIntyre & G. Giribet. 2013. Into the deep: a phylogenetic approach to the bivalve subclass Protobranchia. Mol. Phylogenet. Evol. 69:188-204.
Simpfendorfer, R., M. Vial, D. Lopez, M. Verdala & M. Gonzalez. 1995. Relationship between the aerobic and anaerobic metabolic capacities and the vertical distribution of three intertidal sessile invertebrates: Jehlius cirratus (Darwin) (Cirripedia), Perumytilus purpuratus (Lamarck) (Bivalvia) and Mytilus chilensis (Hupe) (Bivalvia). Comp. Biochem. Physiol. B 111:615-623.
Steinert, G., T. Huelsken, G. Gerlach & O. R. Bininda-Emonds. 2012. Species status and population structure of mussels (Mollusca: Bivalvia: Mytilus spp.) in the Wadden Sea of Lower Saxony (Germany). Org. Divers. Evol. 12:387-402.
Tamura, K., G. Stecher. D. Peterson, A. Fipipski & S. Kumar. 2013. MEGA 6: Molecular Evolutionary Genetics Analysis version 6.0. Mol. Biol. Evol. 30:2725-2729.
Tarifeno, E., R. Galleguillos, A. Llanos-Rivera, D. Arriagada, S. Ferrada, C. B. Canales-Aguirre & M. Seguei. 2012. Identification erronea del mejillon, Mytilus galloprovincialis (Lamarck 1819) como la especie, Mytilus chilensis (Hupe 1854) en la Bahia de Concepcion. Chile. Gayana (Zool.) 76:167-172.
Terranova, M., S. Lo Brutto, M. Arculeo & J. B. Mitton. 2007. A mitochondrial phylogeography of Brachiclontes variabilis (Bivalvia: Mytilidae) reveals three cryptic species. J. Zool. Syst. Evol. Res. 45:289-298.
Toro, J., P. Oyarzun, C. Penaloza, A. Alcapan, V. Videla, J. Tilleria & V. Martinez. 2012. Production and performance of larvae and spat of pure and hybrid species of Mytilus chilensis and M. galloprovincialis from laboratory crosses. Lat. Am. J. Aquat. Res. 40:243-247.
Toro, J. 1998. PCR-based nuclear and mtDNA markers and shell morphology as an approach to study the taxomonic status of the Chilean blue mussel, Mytilus chilensis (Bivalvia). Aquat. Living Resour. 11:347-353.
Toro, J., G. Castro, J. Ojeda & A. Vergara. 2006. Allozymic variation and differentiation in the Chilean blue mussel, Mytilus chilensis, along its natural distribution. Genet. Mol. Biol. 29:174-179.
Toro, J., J. Ojeda & A. Vergara. 2004. The genetic structure of Mytilus chilensis (Hupe 1854) populations along the Chilean coast based on RAPDs analysis. Aquacult. Res. 35:1466-1471.
Uriarte, I. 2008. Estado actual del cultivo de moluscos bivalvos en Chile. In: Lovatelli A., I. Uriarte & A. Farias, editors. Estado actual del cultivo y manejo de moluscos bivalvos y su proyeccion futura. Rome, Italy: FAO. pp. 61-76.
Vainola, R. & P. Strelkov. 2011. Mytilus trossulus in northern Europe. Mar. Biol. 158:817-833.
Vallejos, N., G. Gonzalez, E. Troncoso & R. Zuniga. 2014. Acid and enzyme-aided collagen extraction from the byssus of Chilean mussels (Mytilus chilensis): effect of process parameters on extraction performance. Food Biophys. 9:322-331.
Velasco, L. & J. Navarro. 2002. Feeding physiology of infaunal (Mulinia edulis) and epifaunal (Mytilus chilensis) bivalves under a wide range of concentrations and qualities of seston. Mar. Ecol. Prog. Ser. 240:143-155.
Velasco, L. & J. Navarro. 2003. Energetic balance of infaunal (Mulinia edulis King, 1831) and epifaunal (Mytilus chilensis Hupe, 1854) bivalves in response to wide variations in concentration and quality of seston. J. Exp. Mar. Biol. Ecol. 296:79-92.
Venetis, C., I. Theologidis, E. Zouros & G. C. Rodakis. 2006. No evidence for presence of maternal mitochondrial DNA in the sperm of Mytilus galloprovincialis males. P. Roy. Soc. Lond. B. Bio. 273:2483-2489.
Wares, J. P. & C. W. Cunningham. 2001. Phylogeography and historical ecology of the North Atlantic intertidal. Evolution 55:2455-2469.
Westfall, K. & J. Gardner. 2010. Genetic diversity of Southern Hemisphere blue mussels (Bivalvia: Mytilidae) and the identification of non-indigenous taxa. Biol. J. Linn. Soc. Lond. 101:898-909.
Westfall, K., H. Peter, J. Wimberger & P. Gardner. 2010. An RFLP assay to determine if Mytilus galloprovincialis Lmk. (Mytilidae; Bivalvia) is of Northern or Southern Hemisphere origin. Mol. Ecol. Resour. 10:573-575.
Wilhelm, R. & T. Hilbish. 1998. Assessment of natural selection in a hybrid population of mussels: evaluation of exogenous vs endogenous selection models. Mar. Biol. 131:505-514.
Wood, A., A. Beaumont, D. Skibinski & G. Turner. 2003. Analysis of a nuclear-DNA marker for species identification of adults and larvae in the Mytilus edulis complex. J. Molluscan Stud. 69:61-66.
Wood, A. R., S. Apte, E. S. MacAvoy & J. P. Gardner. 2007. A molecular phylogeny of the marine mussel genus Perna (Bivalvia: Mytilidae) based on nuclear (ITS1&2) and mitochondrial (COI) DNA sequences. Mol. Phylogenet. Evol. 44:685-698.
Zardi, G.I., C. D. McQuaid, P.R. Teske & N. P. Barker. 2007. Unexpected genetic structure of mussel populations in South Africa: indigenous Perna perna and invasive Mytilus galloprovincialis. Mar. Ecol. Prog. Ser. 337:135-144.
MARCELA P. ASTORGA, (1) * LEYLA CARDENAS (2) AND JAIME VARGAS (1)
(1) Instituto de Acuicultura, Universidad Austral de Chile, P.O. 1327, Puerto Mont, Chile; (2) Instituto de Ciencias Ambientales y Evolutivas, Universidad Austral de Chile, Valdivia, Chile
* Corresponding author. E-mail: email@example.com
TABLE 1. Samples of Mytilus species from around the world were used in this work. Samples from South America Locality Abbreviation Lat/Long Tumbes TUM 36[degrees] 36' S/73[degrees] 04' O Puerto Saavedra PSA 38[degrees] 47' S/73[degrees] 23' O Queule QUE 39[degrees] 23' S/73[degrees] 13' O Chaihuin CHA 39[degrees] 56' S/73[degrees] 35' O Huinay HUI 42[degrees] 22' S/72[degrees] 24' O Yaldad YAL 43[degrees] 06' S/73[degrees] 42' O Puerto Balmaceda PRM 43[degrees] 45' S/72[degrees] 58' O Punta Arenas PTA 53[degrees] 25' S/69[degrees] 23' O Puerto Deseado ARG 47[degrees] 45' S/65[degrees] 53' O Montevideo URU 34[degrees] 50' S/56[degrees] 10' O Total Samples from South America Locality N 16S N COI Species Tumbes 10 12 M. galloprovincialis Puerto Saavedra 12 9 Mytilus Queule 15 12 Mvtilus Chaihuin 9 10 Mytilus Huinay 8 13 Mvtilus Yaldad 11 16 Mytilus Puerto Balmaceda 8 11 Mvtilus Punta Arenas 12 29 Mvtilus Puerto Deseado 0 7 Mvtilus Montevideo 7 8 Mvtilus Total 92 127 Samples from South America Locality GenBank 16 /COI Tumbes KP052886-905 / KP052906-927 Puerto Saavedra KM452802-06; KR153801-07 / KR066669-77 Queule KR 153811-20; KM452797-801 / KR066657-68 Chaihuin KR 153794-97; KM452807-11 / KR066678-87 Huinay KR153790-93;834;KM452814-16 / KR066688-700 Yaldad KR3821-26; KM452817-21 / KR066701-16 Puerto Balmaceda KR153198-800; KM452822-26 / KR066717-27 Punta Arenas KP052859-70 / KR066728-56 Puerto Deseado KR066757-63 Montevideo KR 153827-33 / KR066764-71 Total Samples from Other Coasts for COI Locality, Country N Species Dichato, Chile 6 Mytilus sp. Patagonia, Chile 1 Mytilus sp. Maullin, Chile 1 Mytilus sp. Samos, Grecia 7 M. galloprovincialis Morgat, Francia 1 M. galloprovincialis Grecia 1 M. galloprovincialis Auckland, New Zealand 10 M. galloprovincialis Lyttelton, New Zealand 8 M. galloprovincialis Capetown, SouthAfrica 14 M. galloprovincialis Sydney, Australia 15 M. galloprovincialis Campbell, Canada 1 M. galloprovincialis Hobart, Australia 9 M. galloprovincialis Chioggia, Italia 1 M. galloprovincialis Nedlands, Australia Oeste 1 M. galloprovincialis Kerguelen, French 1 M. galloprovincialis New Zealand 3 M. galloprovincialis Tasmania, Australia 2 M. galloprovincialis Kerguelen, French 2 M. galloprovincialis Ciudad del Cabo, South Africa 21 M. galloprovincialis South Africa 1 M. galloprovincialis Atlantico Norte 39 M. galloprovincialis Kanagawa, Japan 1 M. galloprovincialis Roscoff, France 1 M. edulis Greenland 3 M. edulis Atlantico Norte 3 M. edulis Kieler Bucht. Germany 134 M. edulis Mahone Bay, Canada 7 M. trossulus Locality, Country GenBank Haplotype Dichato, Chile AM905174-79 S Patagonia, Chile AM905195 S Maullin, Chile AM905186 5 Samos, Grecia AY 130054-60 N Morgat, Francia AY497292 N Grecia DQ403169 N Auckland, New Zealand DQ864378-87 S Lyttelton, New Zealand DQ864426-33 S Capetown, SouthAfrica DQ864397-410 N Sydney, Australia DQ86411-25 S Campbell, Canada DQ864416 N Hobart, Australia DQ864388-96 S Chioggia, Italia AM905225 N Nedlands, Australia Oeste AM905215 N Kerguelen, French AM905211 S New Zealand AM905146; 49; 55 S Tasmania, Australia AM905161; 62; 65; 68 s Kerguelen, French AM905196-97 N Ciudad del Cabo, South Africa DQ351477-97 N South Africa DQ917605 N Atlantico Norte AF241997-20031; 33-35 N Kanagawa, Japan AB076943 N Roscoff, France AY130053 Greenland EU915572-4 Atlantico Norte AF241969-71 Kieler Bucht. Germany JF825556-689 Mahone Bay, Canada AY130061-67 Locality, Country Reference Dichato, Chile Gerard et al. (2008) Patagonia, Chile Gerard et al. (2008) Maullin, Chile Gerard et al. (2008) Samos, Grecia Riginos et al. (2004) Morgat, Francia Cao et al. (2004) Grecia Venetis et al. (2006) Auckland, New Zealand Unpublished Lyttelton, New Zealand Unpublished Capetown, SouthAfrica Unpublished Sydney, Australia Unpublished Campbell, Canada Unpublished Hobart, Australia Unpublished Chioggia, Italia Gerard et al. (2008) Nedlands, Australia Oeste Gerard et al. (2008) Kerguelen, French Gerard et al. (2008) New Zealand Gerard et al. (2008) Tasmania, Australia Gerard et al. (2008) Kerguelen, French Gerard et al. (2008) Ciudad del Cabo, South Africa Zardi et al. (2007) South Africa Wood et al. (2007) Atlantico Norte Wares and Cumminghan (2001) Kanagawa, Japan Matsumoto (2003) Roscoff, France Riginos et al. (2004) Greenland Riginos and Henzler (2008) Atlantico Norte Wares and Cumminghan (2001) Kieler Bucht. Germany Steinert et al. (2012) Mahone Bay, Canada Riginos et al. (2004) Samples from Other Coasts for 16S Locality N Species GenBank Castro, Chile 1 Mytilus sp. AF179447 Mediterranean Sea 1 M. galloprovincialis DQ836018 South Hemisphere 2 M. galloprovincialis GQ4553981; 88 San Diego, CA 1 M. galloprovincialis MGU22885 Japan 15 M. galloprovincialis KC835224-6; 8; 30-2; 42-6-51 New Zealand 4 M. galloprovincialis AM904568-70; 72; Tasmania 2 M. galloprovincialis AM904579; 80; Kerguelen 2 M. galloprovincialis AM904589; 90; Australia 3 M. galloprovincialis AM904592-94 Australia 1 M. galloprovincialis AF179448 Kerguelen 1 M. galloprovincialis AF179449 New Zealand 2 M. galloprovincialis AF179452-53 Falkland 1 M. galloprovincialis AF179457 New Zealand 1 M. galloprovincialis AF179459 Australia 3 M. galloprovincialis AF179460-62 8 M. galloprovincialis GQ472141-45; 51-53 1 M. galloprovincialis AF317056 Marruecos, 2 M. galloprovincialis KT021638-39 Africa (AFR) Ria Arousa, 3 M. galloprovincialis KT021640-42 Spain (RI) Puerto Balleira, 4 M. galloprovincialis KT021643-46 Spain (PB) Bergen, Norway 2 M. edulis HQ832566; 71 1 M. edulis GQ455405 2 M. edulis AF317054-55 1 M. edulis U22866 3 M. edulis MEU22866-68 Lewes, DE 6 M. edulis AF023546-51 2 M. edulis AJ293730; 38 1 M. edulis KC429249 Kola Bay; 5 M. trossulus HQ832566-70 Gremikha, Russia 1 M. trossulus GQ455404 Japan 5 M. trossulus KC835211; 13; 15; 35; 41 California, 1 M. californianus NC015993 Santa Cruz 1 M. californianus AF317544 1 M. coruscus AF317545 5 M. coruscus GQ472146-50 United Kingdom 1 Mytilus sp. AF023590 Hybrid gallojedulis Locality N Haplotype Reference Castro, Chile 1 S Hilbish et al. (2000) Mediterranean Sea 1 N Terranova et al. (2007) South Hemisphere 2 S Westfall et al. (2010) San Diego, CA 1 N Rawson and Hilbish (1995) Japan 15 N Brannock et al. (2013) New Zealand 4 S Gerard et al. (2008) Tasmania 2 S Gerard et al. (2008) Kerguelen 2 s Gerard et al. (2008) Australia 3 s Gerard et al. (2008) Australia 1 s Hilbish et al. (2000) Kerguelen 1 s Hilbish et al. (2000) New Zealand 2 s Hilbish et al. (2000) Falkland 1 s Hilbish et al. (2000) New Zealand 1 S Hilbish et al. (2000) Australia 3 S Hilbish et al. (2000) 8 n.i. Liu et al. (2011) 1 n.i. Unpublished Marruecos, 2 N Present work Africa (AFR) Ria Arousa, 3 N Present work Spain (RI) Puerto Balleira, 4 N Present work Spain (PB) Bergen, Norway 2 Vainola and Strelkov (2011) 1 Westfall et al. (2010) 2 Unpublished 1 Rawson and Hilbish (1995) 3 Rawson and Hilbish (1995) Lewes, DE 6 Rawson and Hilbish (1995) 2 Unpublished 1 Sharma et al. (2013) Kola Bay; 5 Vainola and Strelkov (2011) Gremikha, Russia 1 Westfall et al. (2010) Japan 5 Brannock et al. (2013) California, 1 Cao et al. (2009) Santa Cruz 1 Unpublished 1 Unpublished 5 Liu et al. (2011) United Kingdom 1 Rawson and Hilbish (1995) n.i., not informated. The GenBank code and the author of the sequences are shown. All of the sequences of Mytilus from South America are indicated in A and were generated in this work. For Mytilus galloprovincialis the haplotype is indicated as either northern (N) or southern (S). TABLE 2. Indices of genetic variability based on mtDNA (COI) sequences for the Mytilus species. Mytilus South America No sequences 117 S (polymorphic sites) 81 Nh 53 Hd 0.927 [+ or -] 0.017 Nucleotide diversity P 0.008 [+ or -] 0.001 No different nucleotides K 4.252 [+ or -] 1.442 Mytilus galloprovincialis- NH No sequences 99 S (polymorphic sites) 31 Nh 28 Hd 0.808 [+ or -] 0.035 Nucleotide diversity P 0.013 [+ or -] 0.002 No different nucleotides K 3.187 [+ or -] 1.084 M. galloprovincialis- SH No sequences 54 S (polymorphic sites) 63 Nh 28 Hd 0.932 [+ or -] 0.021 Nucleotide diversity P 0.038 [+ or -] 0.004 No different nucleotides K 14.185 [+ or -] 4.907 Mytilus edulis No sequences 141 S (polymorphic sites) 48 Nh 41 Hd 0.901 [+ or -] 0.02 Nucleotide diversity P 0.009 [+ or -] 0.0007 No different nucleotides K 3.259 [+ or -] 1.102 Mytilus trossulus No sequences 15 S (polymorphic sites) 16 Nh 12 Hd 0.962 [+ or -] 0.04 Nucleotide diversity P 0.01 [+ or -] 0.001 No different nucleotides K 3.81 [+ or -] 1.451 Nh, number of haplotypes; Hd, haplotypes diversity. Hd, P, and K. with SD. TABLE 3. Indices of genetic variability based on mtDNA (16S) sequences of the Mytilus species. Mytilus Mytilus gullopro South America vincialis-NH No sequences 84 61 S (polymorphic 22 37 sites) Nh 15 17 Hd 0.519 [+ or -] 0.066 0.826 [+ or -] 0.037 Nucleotide 0.002 [+ or -] 0.0005 0.027 [+ or -] 0.004 diversity P No different 0.843 [+ or -] 0.288 9.806 [+ or -] 3.378 nucleotides K M. galloprovincialis- SH Mytilus edulis No sequences 14 25 S (polymorphic 13 33 sites) Nh 10 14 Hd 0.89 [+ or -] 0.081 0.890 [+ or -] 0.052 Nucleotide 0.006 [+ or -] 0.002 0.029 [+ or -] 0.004 diversity P No different 2.198 [+ or -] 0.845 11.053 [+ or -] 3.99 nucleotides K Mytilus trossulus No sequences 18 S (polymorphic 36 sites) Nh 6 Hd 0.627 [+ or -] 0.124 Nucleotide 0.012 [+ or -] 0.009 diversity P No different 4.464 [+ or -] 1.663 nucleotides K Nh, number of haplotypes; Hd, haplotypes diversity. Hd, P, and K with SD. TABLE 4. Estimates of evolutionary divergence between groups using COI sequences. Mytilus Mytilus M. South gullopro galloprovincialis- America vincialis-NH SH Mytilus South 0.007# [+ or -] 0.014 [+ or -] 0.011 America M. 0.035 0.017# [+ or -] 0.016 galloprovincialis- NH M. 0.033 0.041 0.039# galloprovincialis- SH M. edulis 0.030 0.015 0.039 M. trossulus 0.438 0.472 0.490 Mytilus Mytilus edulis trossulus Mytilus South [+ or -] 0.013 [+ or -] 0.199 America M. [+ or -] 0.006 [+ or -] 0.222 galloprovincialis- NH M. [+ or -] 0.015 [+ or -] 0.242 galloprovincialis- SH M. edulis 0.011# [+ or -] 0.202 M. trossulus 0.448 0.011# The number of base substitutions per site averaged over all sequence pairs between groups are shown. SE estimate(s) are shown above the diagonal and were obtained by bootstrapping (1,000 replicates). The number of base substitutions per site averaged over all sequence pairs within each group are shown bold on the diagonal. Analyses were conducted using the Tamura-Nei 93 model + G. The rate variation among sites was modeled with a gamma distribution (shape parameter = 0.241) Note: bold indicated with #. TABLE 5. Estimates of evolutionary divergence between groups using 16S sequences. Mytilus Mytilus M. South gallopro galloprovincialis- America vincialis-NH SH Mytilus South America 0.002# [+ or -] 0.005 [+ or -] 0.001 M. galloprovincialis- 0.019 0.026# [+ or -] 0.005 NH M. galloprovincialis- 0.005 0.021 0.008# SH M. edulis 0.034 0.038 0.036 M. trossulus 0.098 0.103 0.107 Mytilus Mytilus edulis trossulus Mytilus South America [+ or -] 0.008 [+ or -] 0.024 M. galloprovincialis- [+ or -] 0.009 [+ or -] 0.024 NH M. galloprovincialis- [+ or -] 0.008 [+ or -] 0.024 SH M. edulis 0.042# [+ or -] 0.022 M. trossulus 0.100 0.031# The number of base substitutions per site averaged over all sequence pairs between groups are shown. SE estimate(s) are shown above the diagonal. The number of base substitutions per site averaged over all sequence pairs within each group are shown bold on the diagonal. Analyses were conducted using the Tamura-3-parameters model. The rate variation among sites was modeled with a gamma distribution (shape parameter = 0.319) Note: bold indicated with #.
|Printer friendly Cite/link Email Feedback|
|Author:||Astorga, Marcela P.; Cardenas, Leyla; Vargas, Jaime|
|Publication:||Journal of Shellfish Research|
|Date:||Dec 1, 2015|
|Previous Article:||Dynamics of the immune response of the horse mussel Modiolus kurilensis (Bernard, 1983) following challenge with heat-inactivated bacteria.|
|Next Article:||Population ecology and secondary production of congeneric bivalves on a sheltered beach in Southeastern Brazil.|