Genetic heterogeneity in natural beds of the razor clam "Ensis siliqua" revealed by microsatellites

[Abstract] The aim of this study was to analyse the genetic diversity and population structure in the razor clam Ensis siliqua along the European Atlantic coast taking into account their recent history of exploitation and the ‘Prestige' oil spill. To this end we examined the genetic variability of microsatellite markers in 211 razor clams from five populations in Ireland, Portugal and Spain. Microsatellite data revealed a low genetic differentiation between the Spanish and Portuguese populations (FST = 0–0.032) and a moderate differentiation of these populations and the Irish samples (FST = 0.071–0.100). Although we observed changes in genetic diversity in accordance with the level of exploitation and the distribution of the oil spill, these changes were mild and not significant after Bonferroni correction. This could be the result of a genuine low impact, lack of statistical power and/or the capacity of this species to recolonize quickly after the impact of anthropogenic stressors. Supporting the latter argument we found a significant temporal heterogeneity of allelic frequencies in samples coming from the same sampling locality that could be attributed to the movement of adults or larvae from unaffected source populations

Temporal genetic variation of microsatellite markers in the razor clam "Ensis arcuatus" (Bivalvia: Pharidae)

[Abstract] The aim of this study was to characterize new microsatellite loci in the razor clam Ensis arcuatus (Bivalvia: Pharidae) and examine the temporal genetic variability of a natural bed in Cies Islands (Galicia, north-western Spain) exploited by apnoea divers and affected by the ‘Prestige’ oil tanker spill in November 2002. In this work, we characterized four polymorphic microsatellites using an alternative approach that relies on the amplification and sequencing of ISSR markers. Observed heterozygosities ranged from 0.1053–0.6800 and number of alleles from 4–19. Linkage equilibrium was observed in all loci and two of them showed significant deviations from Hardy–Weinberg equilibrium. Estimators of FST between samples were low (<0.05) and not different from zero with a confidence level of 5%. We did not detect a clear decreasing tendency in genetic diversity although we found a significant change in allelic frequencies among samples (P = 0.0024) after the ‘Prestige’ oil spill. We propose that both phenomena could be related to a high variance in genetic success and/or a movement of adults or larvae from different source populations.Xunta de Galicia; PGIDT03PXIB10302PRXunta de Galicia; PGIDT03MA10301PRXunta de Galicia; IN840DXunta de Galicia; IN809

Heterogeneous nature and distribution of interruptions in dinucleotides may indicate the existence of biased substitutions underlying microsatellite evolution

[Abstract] Some aspects of microsatellite evolution, such as the role of base substitutions, are far from being fully understood. To examine the significance of base substitutions underlying the evolution of microsatellites we explored the nature and the distribution of interruptions in dinucleotide repeats from the human genome. The frequencies that we inferred in the repetitive sequences were statistically different from the frequencies observed in other noncoding sequences. Additionally, we detected that the interruptions tended to be towards the ends of the microsatellites and 5′-3′ asymmetry. In all the estimates nucleotides forming the same repetitive motif seem to be affected by different base substitution rates in AC and AG. This tendency itself could generate patterning and similarity in flanking sequences and reconcile these phenomena with the high mutation rate found in flanking sequences without invoking convergent evolution. Nevertheless, our data suggest that there is a regional bias in the substitution pattern of microsatellites. The accumulation of random substitutions alone cannot explain the heterogeneity and the asymmetry of interruptions found in this study or the relative frequency of different compound microsatellites in the human genome. Therefore, we cannot rule out the possibility of a mutational bias leading to convergent or parallel evolution in flanking sequences

Development of Microsatellite Markers in the Razor Clam Solen Marginatus (Bivalvia: Solenidae)

[Abstract] Four microsatellite loci in the razor clam Solen marginatus are described. Loci were isolated from the sequences of intersimple sequence repeat (ISSR) markers and an enriched library. Detailed analysis of these sequences led to the design of eight primer pairs. Allelic variation was assessed in 20 individuals from Redondela, Spain. The genetic variation observed in the markers presented here will be useful for future studies on the population structure of Solen marginatus in the wild and for aquaculture of this species.Xunta de Galicia; PGIDT03MA10301PR

Isolation and characterization of polymorphic microsatellite loci in the razor clam "Ensis siliqua"

[Abstract] Five polymorphic microsatellite loci in the razor clam Ensis siliqua are described. A collection consisting of 34 individuals from Finisterre, Spain, was analysed. Loci were isolated from the sequences of intersimple sequence repeat (ISSR) markers. Detailed analysis of 42 ISSR markers led to the design of 16 primer pairs. Five of these yielded consistent and polymorphic products. The number of alleles ranged from five to 23 per locus with the observed heterozygosity ranging from 0.46 to 0.94. Linkage equilibrium was observed in all loci and three of them showed significant deviations from Hardy–Weinberg equilibrium

Genetic divergence detected by ISSR markers and characterization of microsatellite regions in "Mytilus" mussels

[Abstract] The wide distribution of microsatellites in mussels of the Mytilus edulis complex (Mytilidae) enables the analysis of inter-simple-sequence repeat (ISSR) markers. The aim of this investigation was to assess genetic differentiation in six sampling localities distributed along the European Atlantic coast to expose the potential of these markers in genetic studies requiring the detection of low polymorphism and as a source of sequences for developing microsatellite markers. We detected low genetic structuring within each member of the Mytilus edulis complex. Nei and Li distances and AMOVA clustered the individuals studied into two groups. On the basis of these results two sampling localities coming from the M. edulis × M. galloprovincialis mosaic hybrid zone in Western Europe were assigned to one species. On the other hand, mussels of a sampling locality in the Baltic Sea were not significantly different from a pure M. edulis locality supporting an extensive introgression of M. edulis in these individuals. Finally, 148 microsatellites were found in the sequences of 51 ISSR markers, and two polymorphic microsatellite markers were developed.Xunta de Galicia; PGIDT10PX110304P

Estudos Luso-Hispanos de História do Direito

El primer volumen de los Estudios Luso-Hispanos de Historia del Derecho/ Estudos Luso-Hispanos de História do Direito recoge los trabajos presentados en el ámbito de la segunda edición del EHLHD (Encuentro Hispano-Luso de Historiadores del Derecho/Encontro Hispano-Luso de Historiadores do Direito), celebrado los días 6, 7 y 8 de julio de 2017 en la Universidad Autónoma de Madrid.Presentación / Laura Beck Varela y María Julia Solla Sastre (pp. 9-12). -- Quando il diritto era ancora compatto. Perché la storia giuridica svizzera è così diversa? / Pio Caroni (pp. 13-43). -- El derecho municipal medieval de la Cataluña Nueva (siglos XIII-XVII) / Josep Serrano Daura (pp. 45-62). -- Algunas consideraciones sobre el régimen local cantábrico frente al fomento naval y forestal en la Corona de Castilla (c.1560-1570) / Alfredo José Martínez González (pp. 63-91). -- Organização judiciária e administração da justiça no Portugal filipino: a “reformaçam da justiça” de Filipe I de Portugal (1582) / Jorge Veiga Testos (pp. 93-121). -- El oficio de secretario en la doctrina jurídica de la Edad Moderna / Marina Rojo Gallego-Burín (pp. 123-149). -- Notas sobre la reforma municipal carolina en Sevilla: la representación del común / María del Mar Tizón Ferrer (pp. 151-165). -- Un programa ilustrado para la formación de juristas. El Plan de Estudios de Pablo de Olavide de 1768 / Fernando Liendo Tagle (pp. 167-198). -- La formación del jurista en el virreinato del Perú en las postrimerías del antiguo régimen / Carlos Tormo Camallonga (pp. 199-237). -- Propiedad moderna y alteridad indígena en Brasil (1755-1862) / Camilla de Freitas Macedo (pp. 239-270). -- Direito, política e sociedade: as Novas Conquistas de Goa durante o Perismo. Os contributos de Nery Xavier e Cláudio Lagrange / Luís Pedroso de Lima Cabral de Oliveira y João Pedro Caleira (pp. 271-303). -- Horizonte nacional, espacio tradicional. La construcción jurídica de la nación y el extranjero en la constitución de Cádiz / Iván Pastoriza Martínez (pp. 305-337). -- La disolución de los consejos: entre quiebras, confusiones y continuidad (1834-1836) / Antonio Manuel Luque Reina (pp. 339-371). -- Justicia legal y derecho judicial: la influencia de la jurisprudencia en la formación de la ciencia jurídica isabelina / Blanca Sáenz de Santa María Gómez-Mampaso (pp. 373-409). -- Nuevas etiquetas disciplinares y sus contiendas: las ciencias políticas ante el derecho en Francia (1871-1900) / Pedro Luis López Herráiz (pp. 411-449). -- O casamento na legislação de 1910 em Portugal. A mudança de paradigma nas relações familiares / Miriam Afonso Brigas (pp. 451-479). -- Primeira Lei do Contrato de Trabalho em Portugal: Lei nº 1.952, de 10 de Março de 1937 / Margarida Seixas (pp. 481-513). -- A Revisão Constitucional de 1971: o Projecto de Lei 6/X da “Ala Liberal” num contexto de tensões internas no Marcelismo / Filipe de Arede Nunes (pp. 515-543)