52 research outputs found
THE SPRING MIGRATION OF ADULT NORTH AMERICAN OSPREYS
Most North American Ospreys (Pandion haliaetus) are migratory, breeding in northern latitudes and migrating long distances to and from their wintering grounds in the tropics. Although fall migration patterns of North American Ospreys have been described and studied, very little has been published about the spring migration of these birds. We used satellite telemetry to: (1) determine the characteristics (timing, duration, migratory routes) of spring migrations of Ospreys; (2) determine if differences in spring migration patterns existed between sexes and among three breeding populations (east coast, midwestern, and western); and (3) compare consecutive fall and spring migrations of individual Ospreys. The median dates for departure from the wintering grounds and arrival on the breeding grounds did not differ significantly between adult male and female Ospreys. Compared to their fall migrations, all male and all east coast Ospreys spent fewer days on migration, fewer days in stopover periods along the migration route, traveled shorter distances overall, and traveled farther (on average) each day during spring. In contrast, fall and spring migration characteristics of all female and western Ospreys were similar. Our findings suggest that, although sex and breeding location might influence the spring migration strategy used by individual Ospreys, both males and females minimize the time spent on migration to ensure a timely arrival on the breeding grounds to establish or defend a nesting territory
Upgrading short read animal genome assemblies to chromosome level using comparative genomics and a universal probe set
Most recent initiatives to sequence and assemble new species’ genomes de novo fail to achieve the ultimate endpoint to produce contigs, each representing one whole chromosome. Even the best-assembled genomes (using contemporary technologies) consist of subchromosomal-sized scaffolds. To circumvent this problem, we developed a novel approach that combines computational algorithms to merge scaffolds into chromosomal fragments, PCR-based scaffold verification, and physical mapping to chromosomes. Multigenome-alignment-guided probe selection led to the development of a set of universal avian BAC clones that permit rapid anchoring of multiple scaffolds to chromosomes on all avian genomes. As proof of principle, we assembled genomes of the pigeon (Columbia livia) and peregrine falcon (Falco peregrinus) to chromosome levels comparable, in continuity, to avian reference genomes. Both species are of interest for breeding, cultural, food, and/or environmental reasons. Pigeon has a typical avian karyotype (2n = 80), while falcon (2n = 50) is highly rearranged compared to the avian ancestor. By using chromosome breakpoint data, we established that avian interchromosomal breakpoints appear in the regions of low density of conserved noncoding elements (CNEs) and that the chromosomal fission sites are further limited to long CNE “deserts.” This corresponds with fission being the rarest type of rearrangement in avian genome evolution. High-throughput multiple hybridization and rapid capture strategies using the current BAC set provide the basis for assembling numerous avian (and possibly other reptilian) species, while the overall strategy for scaffold assembly and mapping provides the basis for an approach that (provided metaphases can be generated) could be applied to any animal genome
Kinematics, ages and metallicities for F and G type stars in the solar neighbourhood
A new metallicity distribution and an age-metallicity relation are presented
for 437 nearby F and G turn-off and sub-giant stars selected from radial
velocity data of Nidever et al. Photometric metallicities are derived from
uvby-H\beta photometry, and the stellar ages from the isochrones of Bergbusch &
VandenBerg as transformed to photometry using the methods of Clem et al.
The X (stellar-population) criterion of Schuster et al., which combines both
kinematic and metallicity information, provides 22 thick-disk stars.
\sigma_{\rm W} = 32 \pm 5 km s^{-1}, = 154 \pm 6 km s^{-1} and
= -0.55 \pm 0.03 dex for these thick-disk stars, which is in agreement
with values from previous studies of the thick disk. \alpha -element abundances
which are available for some of these thick-disk stars show the typical
alpha-element signatures of the thick disk, supporting the classification
procedure based on the criteria. Both the scatter in metallicity at a given
age and the presence of old, metal-rich stars in the age-metallicity relation
make it difficult to decide whether or not an age-metallicity relation exists
for the older thin-disk stars. For ages greater than 3 Gyr, our results agree
with the other recent studies that there is almost no correlation between age
and metallicity, \Delta ([M/Fe])/\Delta(age) = -0.01 \pm 0.005 dex Gyr^{-1}.
For the 22 thick-disk stars there is a range in ages of 7-8 Gyr, but again
almost no correlation between age and metallicity.Comment: 11 pages, including 10 figures and 3 tables, accepted for publication
in MNRA
PDBe-KB: a community-driven resource for structural and functional annotations.
The Protein Data Bank in Europe-Knowledge Base (PDBe-KB, https://pdbe-kb.org) is a community-driven, collaborative resource for literature-derived, manually curated and computationally predicted structural and functional annotations of macromolecular structure data, contained in the Protein Data Bank (PDB). The goal of PDBe-KB is two-fold: (i) to increase the visibility and reduce the fragmentation of annotations contributed by specialist data resources, and to make these data more findable, accessible, interoperable and reusable (FAIR) and (ii) to place macromolecular structure data in their biological context, thus facilitating their use by the broader scientific community in fundamental and applied research. Here, we describe the guidelines of this collaborative effort, the current status of contributed data, and the PDBe-KB infrastructure, which includes the data exchange format, the deposition system for added value annotations, the distributable database containing the assembled data, and programmatic access endpoints. We also describe a series of novel web-pages-the PDBe-KB aggregated views of structure data-which combine information on macromolecular structures from many PDB entries. We have recently released the first set of pages in this series, which provide an overview of available structural and functional information for a protein of interest, referenced by a UniProtKB accession
Associating mutations causing cystinuria with disease severity with the aim of providing precision medicine
Background
Cystinuria is an inherited disease that results in the formation of cystine stones in the kidney, which can have serious health complications. Two genes (SLC7A9 and SLC3A1) that form an amino acid transporter are known to be responsible for the disease. Variants that cause the disease disrupt amino acid transport across the cell membrane, leading to the build-up of relatively insoluble cystine, resulting in formation of stones. Assessing the effects of each mutation is critical in order to provide tailored treatment options for patients. We used various computational methods to assess the effects of cystinuria associated mutations, utilising information on protein function, evolutionary conservation and natural population variation of the two genes. We also analysed the ability of some methods to predict the phenotypes of individuals with cystinuria, based on their genotypes, and compared this to clinical data.
Results
Using a literature search, we collated a set of 94 SLC3A1 and 58 SLC7A9 point mutations known to be associated with cystinuria. There are differences in sequence location, evolutionary conservation, allele frequency, and predicted effect on protein function between these mutations and other genetic variants of the same genes that occur in a large population. Structural analysis considered how these mutations might lead to cystinuria. For SLC7A9, many mutations swap hydrophobic amino acids for charged amino acids or vice versa, while others affect known functional sites. For SLC3A1, functional information is currently insufficient to make confident predictions but mutations often result in the loss of hydrogen bonds and largely appear to affect protein stability. Finally, we showed that computational predictions of mutation severity were significantly correlated with the disease phenotypes of patients from a clinical study, despite different methods disagreeing for some of their predictions.
Conclusions
The results of this study are promising and highlight the areas of research which must now be pursued to better understand how mutations in SLC3A1 and SLC7A9 cause cystinuria. The application of our approach to a larger data set is essential, but we have shown that computational methods could play an important role in designing more effective personalised treatment options for patients with cystinuria
Associating mutations causing cystinuria with disease severity with the aim of providing precision medicine
Background
Cystinuria is an inherited disease that results in the formation of cystine stones in the kidney, which can have serious health complications. Two genes (SLC7A9 and SLC3A1) that form an amino acid transporter are known to be responsible for the disease. Variants that cause the disease disrupt amino acid transport across the cell membrane, leading to the build-up of relatively insoluble cystine, resulting in formation of stones. Assessing the effects of each mutation is critical in order to provide tailored treatment options for patients. We used various computational methods to assess the effects of cystinuria associated mutations, utilising information on protein function, evolutionary conservation and natural population variation of the two genes. We also analysed the ability of some methods to predict the phenotypes of individuals with cystinuria, based on their genotypes, and compared this to clinical data.
Results
Using a literature search, we collated a set of 94 SLC3A1 and 58 SLC7A9 point mutations known to be associated with cystinuria. There are differences in sequence location, evolutionary conservation, allele frequency, and predicted effect on protein function between these mutations and other genetic variants of the same genes that occur in a large population. Structural analysis considered how these mutations might lead to cystinuria. For SLC7A9, many mutations swap hydrophobic amino acids for charged amino acids or vice versa, while others affect known functional sites. For SLC3A1, functional information is currently insufficient to make confident predictions but mutations often result in the loss of hydrogen bonds and largely appear to affect protein stability. Finally, we showed that computational predictions of mutation severity were significantly correlated with the disease phenotypes of patients from a clinical study, despite different methods disagreeing for some of their predictions.
Conclusions
The results of this study are promising and highlight the areas of research which must now be pursued to better understand how mutations in SLC3A1 and SLC7A9 cause cystinuria. The application of our approach to a larger data set is essential, but we have shown that computational methods could play an important role in designing more effective personalised treatment options for patients with cystinuria
A QTL for number of teats shows breed specific effects on number of vertebrae in pigs: Bridging the gap between molecular and quantitative genetics
Modern breeding schemes for livestock species accumulate a large amount of genotype
and phenotype data which can be used for genome-wide association studies (GWAS).
Many chromosomal regions harboring effects on quantitative traits have been reported
from these studies, but the underlying causative mutations remain mostly undetected.
In this study, we combine large genotype and phenotype data available from a
commercial pig breeding scheme for three different breeds (Duroc, Landrace, and
Large White) to pinpoint functional variation for a region on porcine chromosome 7
affecting number of teats (NTE). Our results show that refining trait definition by counting
number of vertebrae (NVE) and ribs (RIB) helps to reduce noise from other genetic
variation and increases heritability from 0.28 up to 0.62 NVE and 0.78 RIB in Duroc.
However, in Landrace, the effect of the same QTL on NTE mainly affects NVE and not
RIB, which is reflected in reduced heritability for RIB (0.24) compared to NVE (0.59).
Further, differences in allele frequencies and accuracy of rib counting influence genetic
parameters. Correction for the top SNP does not detect any other QTL effect on NTE,
NVE, or RIB in Landrace or Duroc. At the molecular level, haplotypes derived from 660K
SNP data detects a core haplotype of seven SNPs in Duroc. Sequence analysis of
16 Duroc animals shows that two functional mutations of the Vertnin (VRTN) gene known
to increase number of thoracic vertebrae (ribs) reside on this haplotype. In Landrace,
the linkage disequilibrium (LD) extends over a region of more than 3 Mb also containing
both VRTN mutations. Here, other modifying loci are expected to cause the breedspecific
effect. Additional variants found on the wildtype haplotype surrounding the
VRTN region in all sequenced Landrace animals point toward breed specific differences
which are expected to be present also across the whole genome. This Landrace
specific haplotype contains two missense mutations in the ABCD4 gene, one of which
is expected to have a negative effect on the protein function. Together, the integration of
largescale genotype, phenotype and sequence data shows exemplarily how population
parameters are influenced by underlying variation at the molecular level
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Assembling and comparing avian genomes by molecular cytogenetics
There has been a recent explosion in avian genomics. In December 2014 the Beijing Genomics Institute in collaboration with a number of labs worldwide (including Kent) released 48 new de-novo avian genome sequences in a special edition of Science. This has led to a complete re-evaluation of the phylogenetic tree of birds and presents the opportunity to study avian comparative genomics in far more detail than before. Most of these genome sequences however exist only as “scaffolds” i.e. the depth of sequence and length of read produces contiguous fragments of sub-chromosomal size. This impedes insight into overall genome structure, which is particularly challenging, as one of the most interesting biological features of birds is the peculiarity of their karyotype. This project is an on-going effort to map scaffold assemblies to avian chromosomes using a combination of bioinformatics and Fluorescent in situ Hybridization (FISH). This has traditionally been a very time-consuming and costly procedure, however a combination of bioinformatic approaches coupled with novel hardware innovation has deconstructed the FISH protocol and re-invented it as a high throughput, cheaper procedure. Initial work has helped to reconstruct Pigeon and Peregrine Falcon genomes and will ultimately provide insight into various unanswered questions pertaining to avian gross genome rearrangement. These include why the unique overall genomic structure of birds is so evolutionarily conserved, why intra and inter-chromosomal rearrangements happen (e.g. in response to the development of traits such as vocal learning) and what the karyotypes of extinct species such as dinosaurs may have looked like
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Cooperative carbon capture and steam regeneration with tetraamine-appended metal-organic frameworks.
Natural gas has become the dominant source of electricity in the United States, and technologies capable of efficiently removing carbon dioxide (CO2) from the flue emissions of natural gas-fired power plants could reduce their carbon intensity. However, given the low partial pressure of CO2 in the flue stream, separation of CO2 is particularly challenging. Taking inspiration from the crystal structures of diamine-appended metal-organic frameworks exhibiting two-step cooperative CO2 adsorption, we report a family of robust tetraamine-functionalized frameworks that retain cooperativity, leading to the potential for exceptional efficiency in capturing CO2 under the extreme conditions relevant to natural gas flue emissions. The ordered, multimetal coordination of the tetraamines imparts the materials with extraordinary stability to adsorption-desorption cycling with simulated humid flue gas and enables regeneration using low-temperature steam in lieu of costly pressure or temperature swings
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