Browsing by Author "Pereira, Ana Martins"
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- Absence of consistent genetic differentiation among several morphs of Actinia (Actiniaria: Actiniidae) occurring in the portuguese coastPublication . Pereira, Ana Martins; Brito, Cristiana Maria; Sanches, Joana; Santos, Carla Sousa; Robalo, Joana IsabelActinia equina, the beadlet sea anemone, is a very labile species, displaying variable colour patterns, broad habitat choice and diverse modes of reproduction. Historically, studies using genetic markers such as allozymes and differences in habitat choice lead several authors to propose that different colour morphs could represent different species. One of the species defined was A. fragacea. In this paper, the relationships between brown, red and green colour morphs of A. equina and A. fragacea were studied, using two DNA fragments (one mitochondrial and one nuclear). Individuals were sampled from three different areas in Portugal separated by a maximum distance of 500 km. This is the first study applying direct sequencing of selected gene fragments to approach the validity of Actinia morphs as different genetic entities. The results show that, at least in the Portuguese coast, these colour morphs do not correspond to the two valid species recognized in the literature. The existence of cryptic species is discussed.
- Asexual origin of brooding in the sea anemones Actinia equina and A. schmidti: Molecular evidence from the portuguese shorePublication . Pereira, Ana Martins; Cadeireiro, Emília Margarida; Robalo, Joana IsabelReproduction by sexual or asexual viviparity is a common phenomenon in some anemone species. In this short communication, the origin of the brooded young of Actinia equina and A. schmidti from the Portuguese shore was investigated. DNA was extracted from 56 brooding adult Actinia sp. and the nuclear gene that codes for the 28S ribosomal subunit was sequenced. Species identity was then assessed using GenBank. In total, 50 individuals were A. schmidti, five were A. equina and one had a hybrid origin. Three adult anemones (the hybrid, one A. equina and one A. schmidti) possessed two different 28S sequences and so their offspring was selected for further analysis using the same molecular procedure. Each brooded polyp was found to possess the exact same sequence as its parent, strongly suggesting the asexual origin of broods in A. equina and A. schmidti.
- Broad-scale sampling of primary freshwater fish populations reveals the role of intrinsic traits, inter-basin connectivity, drainage area and latitude on shaping contemporary patterns of genetic diversityPublication . Santos, Carla Sousa; Robalo, Joana Isabel; Pereira, Ana Martins; Branco, Paulo; Santos, José Maria; Ferreira, Maria Teresa; Sousa, Mónica; Doadrio, IgnacioBackground. Worldwide predictions suggest that up to 75% of the freshwater fish species occurring in rivers with reduced discharge could be extinct by 2070 due to the combined effect of climate change and water abstraction. The Mediterranean region is considered to be a hotspot of freshwater fish diversity but also one of the regions where the effects of climate change will be more severe. Iberian cyprinids are currently highly endangered, with over 68% of the species raising some level of conservation concern. Methods. During the FISHATLAS project, the Portuguese hydrographical network was extensively covered (all the 34 river basins and 47 sub-basins) in order to contribute with valuable data on the genetic diversity distribution patterns of native cyprinid species. A total of 188 populations belonging to 16 cyprinid species of Squalius, Luciobarbus, Achondrostoma, Iberochondrostoma, Anaecypris and Pseudochondrostoma were characterized, for a total of 3,678 cytochrome b gene sequences. Results. When the genetic diversity of these populations was mapped, it highlighted differences among populations from the same species and between species with identical distribution areas. Factors shaping the contemporary patterns of genetic diversity were explored and the results revealed the role of latitude, inter-basin connectivity, migratory behaviour, species maximum size, species range and other species intrinsic traits in determining the genetic diversity of sampled populations. Contrastingly, drainage area and hydrological regime (permanent vs. temporary) seem to have no significant effect on genetic diversity. Species intrinsic traits, maximum size attained, inter-basin connectivity and latitude explained over 30% of the haplotype diversity variance and, generally, the levels of diversity were significantly higher for smaller sized species, from connected and southerly river basins. Discussion. Targeting multiple co-distributed species of primary freshwater fish allowed us to assess the relative role of historical versus contemporary factors affecting genetic diversity. Since different patterns were detected for species with identical distribution areas we postulate that contemporary determinants of genetic diversity (species' intrinsic traits and landscape features) must have played a more significant role than historical factors. Implications for conservation in a context of climate change and highly disturbed habitats are detailed, namely the need to focus management and conservation actions on intraspecific genetic data and to frequently conduct combined genetic and demographic surveys.
- Different stocks of brook lamprey in Spain and their origin from Lampetra fluviatilis at two distinct times and placesPublication . Pereira, Ana Martins; Doadrio, Ignacio; Robalo, Joana Isabel; Almada, Vítor CarvalhoUsing the mitochondrial non-coding region I, it was shown that the two Spanish Lampetra planeri populations (Cares–Deva and Olabidea–Ugarana) correspond to different genetic units. The Cares–Deva population is probably a recent offshoot of Lampetra fluviatilis, being the Olabidea–Ugarana population less diverse and of older origin.
- Estudo comparativo do comportamento reproductor de espécies do género Achondrostoma (pisces, cyprinidae)Publication . Pereira, Ana MartinsO presente trabalho pretendeu contribuir para o conhecimento do comportamento reprodutor do género Achondrostoma Robalo, Almada, Levy & Doadrio, 2007. Foram analisadas sequências de comportamentos reprodutores em A. occidentale (Robalo, Almada, Santos, Moreira & Doadrio, 2005), em A. oligolepis (Robalo, Doadrio, Almada & Kottelat, 2005) e numa população de híbridos de duas espécies deste género. Descreveram-se os comportamentos observados nos três grupos e, em alguns casos, foram quantificadas as suas durações. Verificou-se que os comportamentos exibidos eram no essencial os mesmos, diferindo na sua frequência. Assim, em A. occidentale as desovas duraram menos tempo e as fêmeas foram na maioria dos casos pressionadas contra uma superfície rígida durante as desovas, ao passo que em A. oligolepis as desovas foram mais lentas e o comportamento de pressionamento das fêmeas foi observado muito raramente. Por outro lado, observou-se em A. occidentale um comportamento das fêmeas provavelmente de chamamento dos machos, o que já tinha sido descrito em íberochondrostoma lusitanicum (Collares-Pereira, 1980), uma espécie próxima filogeneticamente. Em A oligolepis, foi observado um comportamento dos machos de bloqueio do movimento das fêmeas, observado também em machos de I. lusitanicum no mesmo contexto e que será provavelmente homólogo. Na população de híbridos, as desovas tiveram durações muito mais curtas, e os comportamentos exibidos foram predominantemente os descritos como mais rápidos. Os resultados foram discutidos em termos de estratégias de reprodução e do papel das fêmeas na evolução dos comportamentos reprodutores, assim como em termos de caracterização do comportamento do clade e das diferenças ecológicas das populações.
- Genetic relationships of brook lamprey of the genus Lampetra in a Pyrenean stream in SpainPublication . Pereira, Ana Martins; Almada, Vítor Carvalho; Doadrio, IgnacioThe genetic relationships of a population of brook lamprey Lampetra planeri from Spain were analysed using a fragment of the mitochondrial non-coding region in order to describe its relationships with other European Lampetra populations. DNA sequences were obtained from ten larvae, all corresponding to a single private haplotype. Its closest haplotype differed by five mutations and was found in several samples of Lampetra fluviatlis, both from the North Sea and the Baltic. These results argue for the great conservation value of this brook lamprey population, likely originated from L. fluviatilis ancestors.
- Icelandic lampreys (Petromyzon marinus): Where do they come from?Publication . Pereira, Ana Martins; Jonsson, Benony; Johannsson, Magnus; Robalo, Joana Isabel; Almada, Vítor CarvalhoThe recent discovery of sea lamprey wounds on salmonids in Icelandic rivers prompted an investigation on the origin of sea lampreys in Icelandic waters. Using a mitochondrial DNA fragment, the origin of the lampreys examined was assigned to the European stock and not to the North American one.
- Mito-nuclear sequencing is paramount to correctly identify sympatric hybridizing fishesPublication . Santos, Carla Sousa; Pereira, Ana Martins; Branco, Paulo; Costa, Gonçalo J.; Santos, José M.; Ferreira, Maria Teresa; Lima, Cristina M.; Doadrio, Ignacio; Robalo, Joana IsabelBackground. Hybridization may drive speciation and erode species, especially when intrageneric sympatric species are involved. Five sympatric Luciobarbus species—Luciobarbus sclateri (Günther, 1868), Luciobarbus comizo (Steindachner, 1864), Luciobarbus microcephalus (Almaça, 1967), Luciobarbus guiraonis (Steindachner, 1866), and Luciobarbus steindachneri (Almaça, 1967)—are commonly identified in field surveys by diagnostic morphological characters. Assuming that i) in loco identification is subjective and observer-dependent, ii) there is previous evidence of interspecific hybridization, and iii) the technical reports usually do not include molecular analyses, our main goal was to assess the concordance between in loco species identification based on phenotypic characters with identifications based on morphometric indices, mtDNA only, and a combination of mito-nuclear markers. Materials and methods. Specimens of Luciobarbus from six Guadiana River sub-basins were collected and sequenced for the cytochrome b and beta-actin genes. For comparative purposes, samples of Luciobarbus from other 12 river basins were also used. Four levels of taxonomical identification were conducted based on: identification made in the field (in loco identification), cytb gene only, beta-actin gene only, and mito-nuclear combined genomes. Results. Results showed that interspecific hybridization seems to be high (around 41%) and likely favoured by non-random mating and the loss of fluvial connectivity. About 34% of the hybrids showed mito-nuclear discordance. Misidentifications were frequent when only phenotypic characters are considered, and the use of a single mitochondrial gene is not sufficient: the use of two mito-nuclear markers showed that around 82% of the in loco identifications based on the phenotype were not correct. Conclusion. Incorrect species assignment likely generated biased results in previous studies on the biology and ecology of Guadiana barbels and in the assignment of conservation status and, consequently, on the establishment of conservation management measures.
- Mitochondrial DNA fails to reveal genetic structure in sea-lampreys along european shoresPublication . Almada, Vítor Carvalho; Pereira, Ana Martins; Robalo, Joana Isabel; Fonseca, João Paulo; Levy, André; Maia, Carla; Valente, AlexandreInexistente
- New distribution data on spanish autochthonous species of freshwater fishPublication . Perea, Silvia; Garzón, Paloma; González, José Luis; Almada, Vítor Carvalho; Pereira, Ana Martins; Doadrio, IgnacioOver the last two years (2008-2010) we performed a monitoring project to update the Spanish freshwater fish fauna. We have collected in 785 sampling localities homogeneously distributed throughout Spain each year. We find as the most important result of this study the occurrence of several species that constitute new records for some rivers or basins in Spain: Lampetra planeri, Petromyzon marinus, Barbus haasi, Iberochondrostoma lemmingii, Squalius alburnoides, Squalius carolitertii, Squalius malacitanus, Cobitis calderoni, Cobitis paludica, and Salaria fluviatilis. Finally we corroborate the existence of Barbatula barbatula in the Duero basin and the assignation of the northeastern populations of this genus to B. quignardi.