Browsing by Author "Domingues, Vera dos Santos"
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- Extensive intraspecific polymorphism detected by SSCP at the nuclear C-mos gene in the endemic Iberian lizard Lacerta SchreiberiPublication . Godinho, Raquel; Domingues, Vera dos Santos; Crespo, Eduardo G.; Ferrand, NunoC-mos is a highly conserved intronless gene that has proved useful in the analysis of ancient phylogenetic relationships within vertebrates. We selected the Iberian endemic Schreiber’s green lizard (Lacerta schreiberi) that persisted in allopatric refugia since the late Pliocene to investigate the utility of the Cmos nuclear gene for intraspecific phylogeographic studies. Our combination of DNA sequencing with the high resolving power of single-strand conformational polymorphism (SSCP) effectively discriminated four common alleles showing strong population structuring (FST = 0.46). In addition, reconstruction of allele phylogenetic relationships further improved our understanding of Cmos spatial patterns of variation and allowed a comparison with previously described mitochondrial DNA data. Finally, limited sequencing of an extended Cmos fragment in six additional Lacerta species showed extensive polymorphism, to our knowledge representing a rare example of variation in a highly conserved nuclear gene.
- Genetic divergence in the Atlantic-Mediterranean Montagu's blenny Coryphoblennius galerita revealed by molecular and morphological charactersPublication . Domingues, Vera dos Santos; Faria, Cláudia Barreiros Macedo de; Stefanni, Sergio; Santos, Ricardo Serrão; Brito, Alberto; Almada, Vítor CarvalhoCoryphoblennius galerita is a small intertidal fish with a wide distribution and limited dispersal ability, occurring in the northeastern Atlantic and Mediterranean. In this study, we examined Atlantic and Mediterranean populations of C. galerita to assess levels of genetic divergence across populations and to elucidate historical and contemporary factors underlying the distribution of the genetic variability. We analyse three mitochondrial and one nuclear marker and 18 morphological measurements. The combined dataset clearly supports the existence of two groups of C. galerita : one in the Mediterranean and another in the northeastern Atlantic. The latter group is subdivided in two subgroups: Azores and the remaining northeastern Atlantic locations. Divergence between the Atlantic and the Mediterranean can be the result of historical isolation between the populations of the two basins during the Pleistocene glaciations. Present-day barriers such as the Gibraltar Strait or the ‘Almeria-Oran jet’ are also suggested as responsible for this isolation. Our results show no signs of local extinctions during the Pleistocene glaciations, namely at the Azores, and contrast with the biogeographical pattern that has been observed for Atlantic– Mediterranean warm-water species, in which two groups of populations exist, one including the Mediterranean and the Atlantic coast of western Europe, and another encompassing the western tropical coast of Africa and the Atlantic islands of the Azores, Madeira and Canaries. Species like C. galerita that tolerate cooler waters, may have persisted during the Pleistocene glaciations in moderately affected locations, thus being able to accumulate genetic differences in the more isolated locations such as the Azores and the Mediterranean. This study is one of the first to combine morphological and molecular markers (mitochondrial and nuclear) with variable rates of molecular evolution to the study of the relationships of the Atlantic and Mediterranean populations of a cool-water species.
- Historical colonization and demography of the Mediterranean damselfish, Chromis chromisPublication . Domingues, Vera dos Santos; Bucciarelli, Giuseppe; Almada, Vítor Carvalho; Bernardi, GiacomoThe desiccation of the Mediterranean Sea during the Messinian Salinity Crisis 6.0–5.3 million years ago (Ma), caused a major extinction of the marine ichthyofauna of the Mediterranean. This was followed by an abrupt replenishment of the Mediterranean from the Atlantic after the opening of the Strait of Gibraltar. In this study, we combined demographic and phylogeographic approaches using mitochondrial and nuclear DNA markers to test the alternative hypotheses of where (Atlantic or Mediterranean) and when (before or after the Messinian Salinity Crisis) speciation occurred in the Mediterranean damselfish, Chromis chromis. The closely related geminate transisthmian pair Chromis multilineata and Chromis atrilobata was used as a way of obtaining an internally calibrated molecular clock. We estimated C. chromis speciation timing both by determining the time of divergence between C. chromis and its Atlantic sister species Chromis limbata(0.93–3.26 Ma depending on the molecular marker used, e.g. 1.23–1.39 Ma for the control region), and by determining the time of coalescence for C. chromis based on mitochondrial control region sequences (0.14–0.21 Ma). The time of speciation of C. chromis was always posterior to the replenishment of the Mediterranean basin, after the Messinian Salinity Crisis. Within the Mediterranean, C. chromis population structure and demographic characteristics revealed a genetic break at the Peloponnese, Greece, with directional and eastbound gene flow between western and eastern groups. The eastern group was found to be more recent and with a faster growing population (coalescent time = 0.09–0.13 Ma, growth = 485.3) than the western group (coalescent time = 0.13–0.20 Ma, growth = 325.6). Our data thus suggested a western origin of C. chromis, most likely within the Mediterranean. Low sea water levels during the glacial periods, the hydrographic regime of the Mediterranean and dispersal restriction during the short pelagic larval phase of C. chromis(18–19 days) have probably played an important role in C. chromis historical colonization.
- Historical population dynamics and demography of the eastern Atlantic pomacentrid Chromis limbata (Valenciennes, 1833)Publication . Domingues, Vera dos Santos; Santos, Ricardo Serrão; Brito, Alberto; Almada, Vítor CarvalhoRecent studies have focused on the relationship between the marine fauna of the eastern Atlantic and the Mediterranean Sea, but within the Atlantic, little is known about genetic relationships between populations of the Macaronesian islands. In this study, we tested whether the paleo-climatology and paleo-oceanography of the region could predict the genetic relationships among three eastern Atlantic populations (Azores, Madeira, and Canaries) of a damselWsh, Chromis limbata, and compared our results with its Mediterranean and adjacent Atlantic sister species, Chromis chromis. We combined phylogeographic and coalescent approaches using the fast evolving mitochondrial control region gene. No population structure was found for the three archipelagos. The coalescence time estimated for C. limbata (0.857–1.17Mya) was much greater than that estimated for C. chromis. We propose that this diVerence reXects diVerences in glaciating extents in the Northeastern Atlantic and the Mediterranean. Diversity indexes (Hd and genetic distances) together with historical demographic parameters of C. limbata ( and g) revealed a more stable population history when compared to C. chromis. Our results suggest that the Macaronesian populations of C. limbata have probably been less aVected by the last glaciation than the Mediterranean populations of C. chromis. Migration across the three archipelagos was estimated and a prevailing northwest trend was detected. This result supports the idea of a colonization of the Azores by warm water Wsh from Madeira or the westernmost Canary islands which acted as major glacial refugia for the tropical and subtropical marine fauna during the glaciations.
- Mitochondrial and nuclear markers reveal isolation by distance and effects of Pleistocene glaciations in the northeastern Atlantic and Mediterranean populations of the white seabream (Diplodus sargus, L.)Publication . Domingues, Vera dos Santos; Santos, Ricardo Serrão; Brito, Alberto; Alexandrou, Markos; Almada, Vítor CarvalhoPhylogeography of Diplodus sargus from the northeastern Atlantic and the Mediterranean was assessed using sequences from the mitochondrial control region and the first intron of the S7 ribosomal protein gene. The relationship between genetic and geographic distances supported an isolation by distance model, with the Azores having a peripheral position. The geographic distribution of the genetic diversity, together with the historical demography of the populations studied can be explained by the effect of the Pleistocene glaciations in the northeastern Atlantic warm water fauna. D. sargus might have disappeared from western Europe during glacial peaks and suffered considerable demographic reductions in the Canaries and Mauritania, surviving in less affected areas such as Madeira, Azores and the Mediterranean. The mismatch analysis and the Fu's Fs values provide clear evidence of expansion in western Iberia (S. Pedro), Canaries, Mauritania and also in the eastern Mediterranean. Atlantic and Mediterranean populations of D. sargus showed no signs of genetic differentiation. D. sargus are active swimmers that can undergo extensive movements along the shores. This and the presence of planktonic eggs and larvae would allow rapid mixing between Mediterranean and Atlantic fish, erasing signs of population differentiation.
- Molecular data confirm the validity of the portuguese blenny (Parablennius ruber, Valenciennes, 1836) and its presence in Western EuropePublication . Almada, Vítor Carvalho; Domingues, Vera dos Santos; Monteiro, Nuno Miguel; Almada, Frederico José Oliveira de; Santos, Ricardo SerrãoDNA sequence analysis confirms the distinction between Parablennius ruber and Parablennius gattorugine, simultaneously validating the presence of the former species in Western Europe where it has been reported for >150 years. A possible scenario involving speciation of P. ruber at the Azores and subsequent transport of larvae to Europe, a process that may be still occurring nowadays, could explain this pattern of occurrence.
- Molecular validation of the specific status of Parablennius sanguinolentus and Parablennius parvicornis (Pisces: Blenniidae)Publication . Almada, Frederico José Oliveira de; Almada, Vítor Carvalho; Domingues, Vera dos Santos; Brito, Alberto; Santos, Ricardo SerrãoParablennius sanguinolentus and P. parvicornis have been classified as either two distinct species or as two sub-species depending on the different criteria used to classify them. An analysis of fragments of mitochondrial 12S and 16S rDNA showed that the genetic distance between samples of P. sanguinolentus and P. parvicornis is similar or higher than those found for other blenniids that are widely recognized as distinct species. These results, together with the distinct geographical distributions and meristic differences, support the conclusion that P. sanguinolentus and P. parvicornis should be considered as two different species.
- Phylogeny of the shanny, Lipophrys pholis, from the NE Atlantic using mitochondrial DNA markersPublication . Stefanni, Sergio; Domingues, Vera dos Santos; Bouton, Niels; Santos, Ricardo Serrão; Almada, Frederico José Oliveira de; Almada, Vítor CarvalhoInexistente
- Phylogeography and demography of the Blenniid Parablennius parvicornis and its sister species P. sanguinolentus from the northeastern Atlantic Ocean and the western Mediterranean SeaPublication . Domingues, Vera dos Santos; Stefanni, Sergio; Brito, Alberto; Santos, Ricardo Serrão; Almada, Vítor CarvalhoInexistente
- Phylogeography and evolution of the triplefin Tripterygion delaisi (Pisces, Blennioidei)Publication . Domingues, Vera dos Santos; Almada, Vítor Carvalho; Santos, Ricardo Serrão; Brito, Alberto; Bernardi, GiacomoThe genus Tripterygion (Risso 1826) is restricted to the eastern Atlantic and the Mediterranean, and comprises only three species. T. melanuros and T. tripteronotus are essentially endemic to the Mediterranean, while Tripterygion delaisi occurs in the Atlantic and in the Mediterranean. Two subspecies of T. delaisi have been described (T. d. xanthosoma in the Mediterranean and T. d. delaisi in the Atlantic). Several scenarios have been proposed for the evolution of T. delaisi subspecies, but so far its subspeciation process is not clear. In this study we present a population survey of T. delaisi including specimens from the two recognized subspecies. We combined a phylogeographic approach with estimates of the direction of migration (between the Atlantic and the Mediterranean) and of the coalescence time of the two subspecies, using polymorphic mitochondrial and nuclear genes. The results of this study clearly support the existence of two Tripterygion delaisi clades, one in the eastern Atlantic islands and another in the Atlantic coasts of Europe and in the Mediterranean. Historical migration between the islands and Western Europe plus Mediterranean was restricted, and showed a westbound trend, with a higher number of migrants going from the Western Europe plus Mediterranean into the islands. We estimated the time of coalescence of both groups of T. delaisi to be more recent than the onset of Pleistocene glaciations (1.7 Mya). Our results are consistent with previous hypothesis that consider successive dispersal events of a Tripterygion ancestor from the western African coast colonizing the Atlantic islands and the Mediterranean, promoting the evolutionary divergence between these areas.