313 research outputs found
Long prereproductive selection and divergence by depth in a caribbean candelabrum coral
Long-lived corals, the foundation of modern reefs, often follow ecological gradients, so that populations or sister species segregate by habitat. Adaptive divergence maintains sympatric congeners after secondary contact or may even generate species by natural selection in the face of gene flow. Such ecological divergence, initially between alternative phenotypes within populations, may be aided by immigrant inviability, especially when a long period separates larval dispersal and the onset of reproduction, during which selection can sort lineages to match different habitats. Here, we evaluate the strength of one ecological factor (depth) to isolate populations by comparing the genes and morphologies of pairs of depth-segregated populations of the candelabrum coral Eunicea flexuosa across the Caribbean. Eunicea is endemic to the Caribbean and all sister species co-occur. Eunicea flexuosa is widespread both geographically and across reef habitats. Our genetic analysis revealed two depth-segregated lineages. Field survivorship data, combined with estimates of selection coefficients based on transplant experiments, suggest that selection is strong enough to segregate these two lineages. Genetic exchange between the Shallow and Deep lineages occurred either immediately after divergence or the two have diverged with gene flow. Migration occurs asymmetrically from the Shallow to Deep lineage. Limited recruitment to reproductive age, even under weak annual selection advantage, is sufficient to generate habitat segregation because of the cumulative prolonged prereproductive selection. Ecological factors associated with depth can act as filters generating strong barriers to gene flow, altering morphologies, and contributing to the potential for speciation in the sea
Getting a grip at the edge: recolonization and introgression in eastern Pacific Porites corals
© 2016 John Wiley & Sons Ltd Aim: To infer species identity, population isolation, and geographical variation in inter-specific hybridization among corals of the genus Porites from the central and eastern tropical Pacific, with a focus on the timing of separation between populations of P. evermanni and P. lobata divided by the Eastern Pacific Barrier. Location: Hawaii, American Samoa, Panama and the Galapagos Islands of Ecuador. Methods: Maximum likelihood gene trees were obtained for mitochondrial DNA (COI), the internal transcribed spacer (ITS), and 5 single-copy nuclear (scn) gene regions. Allelic networks were used to group multi-locus scn data into species clusters despite some allele sharing. Coalescent analyses (IMa2) of the 5 scn markers were used to estimate the time of population divergence and test for introgression between P. evermanni and P. lobata. Results: Allelic networks based on scn gene sequences agreed with mtCOI and ITS designations. Divergence times between Hawaiian and eastern Pacific populations are consistent with an early Pleistocene recolonization of the eastern Pacific by P. evermanni followed by a more recent arrival of P. lobata. The two species were fully isolated in Hawaii/American Samoa populations, but introgression from P. evermanni into P. lobata was evident in the eastern Pacific. Main conclusions: These results are consistent with a scenario where a bout of introgression with P. evermanni, an early-arriving colonizer of the eastern Pacific suited to marginal environmental conditions, facilitated the later colonization of the more sensitive P. lobata
NAA10 p.(N101K) disrupts N-terminal acetyltransferase complex NatA and is associated with developmental delay and hemihypertrophy
Nearly half of all human proteins are acetylated at their N-termini by the NatA N-terminal acetyltransferase complex. NAA10 is evolutionarily conserved as the catalytic subunit of NatA in complex with NAA15, but may also have NatA-independent functions. Several NAA10 variants are associated with genetic disorders. The phenotypic spectrum includes developmental delay, intellectual disability, and cardiac abnormalities. Here, we have identified the previously undescribed NAA10 c.303C>A and c.303C>G p.(N101K) variants in two unrelated girls. These girls have developmental delay, but they both also display hemihypertrophy a feature normally not observed or registered among these cases. Functional studies revealed that NAA10 p.(N101K) is completely impaired in its ability to bind NAA15 and to form an enzymatically active NatA complex. In contrast, the integrity of NAA10 p.(N101K) as a monomeric acetyltransferase is intact. Thus, this NAA10 variant may represent the best example of the impact of NatA mediated N-terminal acetylation, isolated from other potential NAA10-mediated cellular functions and may provide important insights into the phenotypes observed in individuals expressing pathogenic NAA10 variants.publishedVersio
Clinicopathologic study on the effects of Glyphosate (Roundup?) at sublethal levels in a murine experimental model
P?ginas 17-24Recurso Electr?nicoEn Colombia, los pesticidas a base de glifosato se usan para el control de malezas en la agricultura y erradicaci?n de cultivos il?citos. Sin embargo, los efectos t?xicos en animales y humanos expuestos a dosis subletales son desconocidos. Este estudio evalu? los efectos cl?nico-patol?gicos de dietas con 7,5 ppm y 15 ppm glifosato en ratones Mus musculus gestantes, usando el herbicida Roundup?. Se registr? el peso corporal de las hembras, de sus cr?as, y la viabilidad de las camadas diariamente. Las lesiones macrosc?picas e histopatol?gicas en el h?gado, ri??n, ?tero y cerebro se determinaron a trav?s de necropsias en los d?as 5, 30 y 45 despu?s de la exposici?n, adem?s de los ?ndices org?nicos hep?tico y cardiaco. No hubo diferencias significativas en el peso corporal, el tama?o y la viabilidad de las camadas a ninguna de las dosis evaluadas. Se observ? congesti?n y aumento en el tama?o del h?gado, ri??n y bazo, despu?s de 5 d?as de exposici?n, sugiriendo un proceso de desintoxicaci?n. A 30 y 45 d?as, no se observaron signos cl?nicos ni lesiones patol?gicas atribuibles al glifosato; sin embargo, un aumento en el tama?o de los hepatocitos, con contenido vacuolar y granular de aspecto protein?ceo indican un efecto evidente, aunque sutil del Roundup? a dosis subletales con posible adaptabilidad org?nica. Se concluye que el consumo de alimento con 7,5 ppm y 15 ppm de glifosato durante 5, 30 y 45 d?as causa alteraciones sutiles de toxicidad en ratones durante la gestaci?n, la lactancia y el posparto, pero no en sus camadas.ABSTRACT. In Colombia, glyphosate-based pesticides are used for weed control in agriculture and eradication of illicit crops; however, the toxic effects in animals and humans exposed to sublethal doses are unknown. This study evaluated the clinical and pathological changes induced by diets containing glyphosate at 7,5 ppm and 15 ppm in pregnant mice Mus musculus, using the herbicide Roundup ?. The body-weight of pregnant females and offspring and the viability of litters were recorded daily. Gross and microscopic lesions in liver, kidney, uterus and brain were determined at necropsies performed at 5, 30 and 45 days post- exposure, in addition to the liver and heart organic indexes. No significant differences were found in body weight, size and viability of litters at any dose. Organs such as the liver, kidney and spleen were enlarged and congested at day 5 post exposure, suggesting a detoxification process. At 30 and 45 days, no clinical signs or pathological lesions attributed to glyphosate were found. However, there was an increase in the hepatocyte size, with vacuolar and granular cytoplasm and proteinaceus-like content, suggesting a subtle effect of sublethal doses of Roundup ?, with possible organ adaptability. We conclude that the consumption of food containing 7.5 ppm and 15 ppm of glyphosate for 5, 30 and 45 days, cause subtle toxic alterations in mice during pregnancy, lactation and postpartum, but not in their litters
Degradabilidade in situ de hÃbridos de milho e de capim-elefante colhidos em quatro estádios de maturidade
Dentre as forragens, a silagem de milho é amplamente utilizada pelos fazendeiros que visam explorar o máximo do potencial genético dos animais. No entanto, outros volumosos tropicais como o capim-elefante (Pennisetum purpureum) são mais produtivos e, portanto, mais baratos do que a silagem de milho. Nosso objetivo foi comparar a degradabilidade in situ do capim-elefante com a degradabilidade de hÃbridos de milho, colhidos em quatro estágios de maturidade. O experimento seguiu um delineamento de blocos ao acaso com sub-parcelas. Dois hÃbridos de milho: AG5011 e ZN8392 foram colhidos com 25, 30, 35 e 40% matéria seca (MS) na planta toda e separados na fração colmo + bainha + folhas e espigas. Capim elefante foi colhido 30, 40, 50 e 60 dias após o corte de nivelamento. As amostras secas e trituradas foram incubadas no rúmen por 0, 6, 12, 24, 48 e 72 h para cálculo da cinética da degradação ruminal da MS e da fibra em detergente neutro (FDN). O avanço da maturidade aumentou os teores de FDN e fibra em detergente ácido (FDA) do capim elefante e reduziu a degradabilidade da MS. Entretanto, a maturidade teve pouco efeito sobre os teores de fibra e a degradabilidade da MS da fração planta dos hÃbridos de milho. O capim elefante apresentou maior degradabilidade da FDN do que hÃbridos de milho, e não houve efeito da maturidade sobre a degradabilidade da FDN das duas espécies. A degradabilidade da fibra de capim-elefante não é pior do que a de hÃbridos de milho e, portanto a escolha da forragem deve ser feita com base em análises econômicas ao invés de assumir um menor potencial de produção em dietas a base de capim elefanteAmong tropical forages, corn silage is largely used by farmers trying to explore the maximum genetic potential from the animals. However, other tropical forages, such as elephant-grass (Pennisetum purpureum), are more productive and therefore cheaper to use than corn silage. Our objective was to compare the in situ degradability of elephant-grass with that from corn hybrids, all harvested at four stages of maturity. The experimental design followed a randomized block design with nested subplots. Two corn hybrids: AG5011, ZN8392 were harvested with 25, 30, 35, and 40% dry matter (DM) in the whole plant, and separated in stem + leaf sheath + leaf blade (stover), and cobs. Elephant-grass was harvested with 30, 40, 50 and 60 days after a leveling cut. Dried and ground samples were incubated in nylon bags inside the rumen for 0, 6, 12, 24, 48 and 72 h to estimate the kinetics of ruminal DM and neutral detergent fiber (NDF) degradation. The advance of maturity increased the NDF and acid detergent fiber (ADF) content in elephant-grass, and reduced its DM degradability. However, maturity had little or no effect on fiber content and DM degradability of corn stover. Elephant-grass had a higher NDF degradability than corn stover, and there was no effect of maturity on NDF degradability of either elephant-grass or corn stover. Fiber degradability of elephant-grass was not worse than that of corn stover, and therefore the choice of forage should be made on economical analysis rather than assuming an intrinsic low production potential for elephant-grass based diet
Stochastic bias of colour-selected BAO tracers by joint clustering-weak lensing analysis
The baryon acoustic oscillation (BAO) feature in the two-point correlation
function of galaxies supplies a standard ruler to probe the expansion history
of the Universe. We study here several galaxy selection schemes, aiming at
building an emission-line galaxy (ELG) sample in the redshift range
, that would be suitable for future BAO studies, providing a highly
biased galaxy sample. We analyse the angular galaxy clustering of galaxy
selections at the redshifts 0.5, 0.7, 0.8, 1 and 1.2 and we combine this
analysis with a halo occupation distribution (HOD) model to derive the
properties of the haloes these galaxies inhabit, in particular the galaxy bias
on large scales. We also perform a weak lensing analysis (aperture statistics)
to extract the galaxy bias and the cross-correlation coefficient and compare to
the HOD prediction.
We apply this analysis on a data set composed of the photometry of the deep
co-addition on Sloan Digital Sky Survey (SDSS) Stripe 82 (225 deg), of
Canda-France-Hawai Telescope/Stripe 82 deep \emph{i}-band weak lensing survey
and of the {\it Wide-Field Infrared Survey Explorer}infrared photometric band
W1.
The analysis on the SDSS-III/constant mass galaxies selection at is
in agreement with previous studies on the tracer, moreover we measure its
cross-correlation coefficient . For the higher redshift bins, we
confirm the trends that the brightest galaxy populations selected are strongly
biased (), but we are limited by current data sets depth to derive
precise values of the galaxy bias. A survey using such tracers of the mass
field will guarantee a high significance detection of the BAO.Comment: 17 pages, 15 figures, submitted to MNRA
Database of Seismic Intensities for Colombia and Western Venezuela
Este artÃculo presenta una base de datos de intensidades sÃsmicas recopiladas para Colombia y el Occidente de Venezuela. Esta base de datos macrosÃsmica está basada en la recopilación y análisis de información contenida en mapas de isosistas generada por diferentes investigadores en el Norte de Suramérica. La base de datos incluye 68 eventos sÃsmicos ocurridos entre 1766 y 2004. Para estos eventos, se presentan 283 pares de datos de intensidad – radio equivalente. El presente trabajo constituye la base para futuras investigaciones cuyo objetivo sea mejorar el entendimiento de la atenuación de la energÃa sÃsmica en la región.This article presents an extensive database of seismic intensities compiled for Colombia and Western Venezuela. This macroseismal database is based upon the compilation and analysis of information contained in isoseismal maps produced mainly by researchers in Colombia and Venezuela. The database includes 68 earthquake events, which happened between 1766 and 2004. For these events 283 pairs of Modified Mercalli intensity points and the radii of equivalent isoseismals are presented. This work constitutes the basis for future investigations aimed at improving the understanding of the attenuation of seismic energy in the region. It is considered that the database presented may play a central role in future studies of hazard based on intensity
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