Genetic characterization of the canarian sheep with microsatellites

The Canarian sheep is an autochthonous breed used for milk production. In this work 28 microsatellite markers are used to characterize this population. Samples from different breeders are collected randomly and allelic frequencies, heterozygosity and Fis has been calculated. The main conclusion is that it is an ovine breed with an elevated genetic diversity and homogeneity. This study constitutes the first step for any management strategy because it permits to know the genetic situation of the breed, to design a microsatellite panel for parentage test, to establish the genetic relationships with other ovine populations, to assign individuals to populations or traceability of derived products.Se ha caracterizado genéticamente una población de oveja Canaria, raza autóctona dedicada a la producción de leche, con 28 microsatélites de ADN. Se han calculado frecuencias alélicas, heterocigosidad y Fis. Puede concluirse que se trata de una raza ovina con elevada diversidad genética y que es genéticamente homogénea. Este estudio es básico para cualquier estrategia de gestión de la raza pues se conoce su situación genética. A partir de este punto puede abordarse el control de la genealogía con marcadores moleculares pues, con los resultados obtenidos, puede diseñarse un panel de microsatélites (8-10) para control de paternidad. También se pueden estudiar sus relaciones genéticas con otras poblaciones ovinas españolas o extranjeras, o la asignación de individuos a poblaciones o trazabilidad de productos derivados de esta raza

Evidence for a supercooled plastic-crystal phase in solid ethanol

The existence of an orientationally disordered cubic phase of solid ethanol is revealed by x-ray diffraction and Raman spectroscopic measurements. Such a phase, whose existence was postulated some time ago on the basis of specific-heat measurements, is produced by quenching below some 95 K a plastic crystal formed upon melting and subsequent annealing of the topologically disordered (glassy) solid. The relevance of the present findings for current discussions on glassy dynamics is analyzed in some detail.Dirección General de Investigaciones Científicas y Técnicas PB92-0114-C0

Microscopic dynamics of glycerol in its crystalline and glassy states

The dynamics of crystalline glycerol are studied by means of Raman spectroscopy and lattice dynamics calculations employing a semiflexible model to represent the low-lying molecular vibrations. The latter is validated against structural, thermodynamic, and spectroscopic data. The results serve to set an absolute frequency scale for glassy glycerol, which is also studied by Raman and incoherent inelastic-neutron scattering. Some implications of the present findings regarding ensuing discussions on glassy dynamics are finally commented on.Dirección General de Investigaciones Científicas y Técnicas PB92- 0114-C0

Thermal transport in glassy selenium: The role of low-frequency librations

The experimental curves giving the temperature dependence of the thermal conductivity of glassy selenium are considered in detail. The observed behavior can be taken into account quantitatively if the densities of states for short-wavelength phonons as well as for low-energy librations arising from computer simulations are used for the calculations. In particular, it is shown that the lowest frequency excitations of a chain of selenium atoms can give due account of the plateau observed at temperatures about 2-10 K. The implications of the present findings for the current debate regarding the mechanisms for thermal transport in glasses are finally discussedDirección General de Investigación Científica y Técnica PB92-0114-C0

Genetic characterisation of the palmera sheep with microsatellites

It have been studied 178 animals (the whole population) of the Palmera sheep with 24 microsatellites in order to characterise this autochthonous breed from La Palma Island (Canary Islands, Spain). Ovine and bovine microsatellites recommended by FAO, ISAG (International Society of Animal Genetics) and other authors in the bibliography for ovine biodiversity studies have been used. These markers were amplified by mean of the polymerase chain reaction (PCR) technique and to get the size separation of the obtained fragments we have developed electrophoresis in polyacrylamide gel in an automatic sequencer ABI377XL. All the microsatellites have been polymorphic and between 2 (ETH10) and 15 (CSSM66) alleles have been found with an average value of 7.04. The expected heterozigosity has been 0,6039 and the observed heterozigosity 0.5504. The paternity and maternity have been checked with these microsatellites and this has been used to make a paternity panel with 10-12 markers and an a priori exclusion probability higher than 99,9 percent. This panel is useful to check paternity in this threatened breed.Se estudian 178 animales pertenecientes a la raza ovina Palmera, lo que supone la totalidad de la población, mediante 24 marcadores microsatélites con objeto de caracterizar esta raza autóctona de la Isla de la Palma (Islas Canarias, España). Se han empleado microsatélites de ovino y de bovino recomendados por la FAO, por la ISAG (International Society of Animal Genetics) y por otros autores en la bibliografía para este tipo de estudios en ovinos. Los microsatélites se han amplificado mediante la reacción en cadena de la polimerasa (PCR) y los fragmentos amplificados se han separado mediante electroforesis en un secuenciador automático ABI 377XL. Todos los microsatélites utilizados han resultado polimórficos y se han encontrado entre 2 alelos para el ETH10 y 15 para el CSSM66, con un número medio de alelos de 7,04. La heterocigosidad media esperada ha sido 0,6039 y la observada 0,5504. Se ha llevado a cabo también la comprobación de paternidades y maternidades con estos microsatélites, lo que ha servido para establecer una batería de 10-12 microsatélites con una probabilidad de exclusión a priori superior al 99,9 p.100 que puede resultar muy útil para realizar controles de filiación en esta raza ovina en serio peligro de extinción

Genetic characterisation of the mostrenca cattle with microsatellites

In this work the Mostrenca bovine population that lives in the Estación Biológica de Doñana (340 animals) has been studied with 26 microsatellites recommended by FAO for bovine biodiversity studies. The 9 microsatellites of the international panel for parentage control are included in this study. These markers were amplified by mean of the polymerase chain reaction (PCR) technique and to get the size separation of the obtained fragments we have developed electrophoresis in polyacrylamide gel in an automatic sequencer ABI377XL. All the microsatellites have been polymorphic and between 3 (BM8125) and 10 (ETH225) alleles have been found with an average value of 6,7. The expected heterozigosity has been 0.6244 and the observed heterozigosity 0.6115. The paternity and maternity have been checked with these microsatellites and this has been used to make a paternity panel with 10-12 markers and an a priori exclusion probability higher than 99.9 percent. This panel is useful to check paternity in this bovine breed that have a very special management: it is a feral breed that lives inside a restricted biologic reserve where the livestock is not allowed.En este trabajo se caracteriza la población bovina Mostrenca de la Estación Biológica de Doñana (340 muestras) con 26 microsatélites de ADN recomendados por la FAO para estudios de biodiversidad bovina y entre los que se encuentran los 9 marcadores del panel internacional para pruebas de paternidad en bovino. Los microsatélites se han amplificado mediante la reacción en cadena de la polimerasa (PCR) y los fragmentos amplificados se han separado mediante electroforesis en un secuenciador automático ABI 377XL. Todos los microsatélites utilizados han resultado polimórficos y se han encontrado entre 3 alelos para el BM8125 y 10 para el ETH225, con un número medio de alelos de 6,7. La heterocigosidad media esperada ha sido 0,6244 y la observada 0,6115. Se ha llevado a cabo la comprobación de paternidades y maternidades con estos microsatélites, lo que ha servido para establecer una batería de 10-12 microsatélites con una probabilidad de exclusión a priori superior al 99,9 p.100 que puede resultar muy útil para realizar controles de filiación en esta raza bovina con unas peculiaridades de manejo muy especiales dada su condición de raza en estado asilvestrado dentro de una reserva biológica protegida en la que no está permitida la ganadería como tal