50 research outputs found
Characterization of copy number variants in a large multibreed population of beef and dairy cattle using high-density single nucleotide polymorphism genotype data
Copy number variants (CNVs)
are a form of genomic variation that changes
the structure of the genome through deletion or
duplication of stretches of DNA. The objective
of the present study was to characterize CNVs in
a large multibreed population of beef and dairy
bulls. The CNVs were called on the autosomes
of 5,551 cattle from 22 different beef and dairy
breeds, using 2 freely available software suites,
QuantiSNP and PennCNV. All CNVs were classified into either deletions or duplications. The
median concordance between PennCNV and
QuantiSNP, per animal, was 18.5% for deletions
and 0% for duplications. The low concordance
rate between PennCNV and QuantiSNP indicated
that neither algorithm, by itself, could identify
all CNVs in the population. In total, PennCNV
and QuantiSNP collectively identified 747,129
deletions and 432,523 duplications; 80.2% of all
duplications and 69.1% of all deletions were present only once in the population. Only 0.154% of
all CNVs identified were present in more than 50
animals in the population. The distribution of the
percentage of the autosomes that were composed
of deletions, per animal, was positively skewed,
as was the distribution for the percentage of the
autosomes that were composed of duplications,
per animal. The first quartile, median, and third
quartile of the distribution of the percentage of
the autosomes that were composed of deletions
were 0.019%, 0.037%, and 0.201%, respectively.
The first quartile, median, and third quartile of the
distribution of the percentage of the autosomes
that were composed of duplications were 0.013%,
0.028%, and 0.076%, respectively. The distributions of the number of deletions and duplications
per animal were both positively skewed. The interquartile range for the number of deletions per animal in the population was between 16 and 117,
whereas for duplications it was between 8 and
23. Per animal, there tended to be twice as many
deletions as duplications. The distribution of the
length of deletions was positively skewed, as was
the distribution of the length of duplications. The
interquartile range for the length of deletions in
the population was between 25 and 101 kb, and for
duplications the interquartile range was between
46 and 235 kb. Per animal, duplications tended to
be twice as long as deletions. This study provides a
description of the characteristics and distribution
of CNVs in a large multibreed population of beef
and dairy cattle
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Field method for preservation of total mercury in waters, including those associated with artisanal scale gold mining â
Analysis of mercury (Hg) in natural water samples has routinely been impractical in many environments, for example, artisanal and small-scale gold mines (ASGM), where difficult conditions make monitoring of harmful elements and chemicals used in the processes highly challenging. Current sampling methods require the use of hazardous or expensive materials, and so difficulties in sample collection and transport are elevated. To solve this problem, a solid-phase extraction-based method was developed for the sampling and preservation of dissolved Hg in natural water samples, particularly those found around ASGM sites. Recoveries of 85% ± 10% total Hg were obtained during 4 weeks of storage in refrigerated (4 °C, dark) and unrefrigerated (16 °C, dark) conditions, and from a representative river water spiked to 1 ÎŒg Lâ1 Hg2+, 94% ± 1% Hg recovery was obtained. Solid-phase extraction loading flow rates were tested at 2, 5, and 10 mL minâ1 with no breakthrough of Hg, and sorbent stability showed no breakthrough of Hg up to 2 weeks after functionalisation. The method was deployed across five artisanal gold mines in Kakamega gold belt, Kenya, to assess Hg concentrations in mine shaft water, ore washing ponds, and river and stream water, including drinking water sources. In all waters, Hg concentrations were below the WHO guideline limit value of 6 ÎŒg Lâ1, but drinking water sources contained trace concentrations of up to 0.35 ÎŒg Lâ1 total Hg, which may result in negative health effects from long-term exposure. The SPE method developed and deployed here is a robust sampling method that can therefore be applied in future Hg monitoring, toxicology, and environmental work to provide improved data that is representative of total dissolved Hg in water samples
Exploring hypotheses of the actions of TGF-beta 1 in epidermal wound healing using a 3D computational multiscale model of the human epidermis
In vivo and in vitro studies give a paradoxical picture of the actions of the key regulatory factor TGF-beta 1 in epidermal wound healing with it stimulating migration of keratinocytes but also inhibiting their proliferation. To try to reconcile these into an easily visualized 3D model of wound healing amenable for experimentation by cell biologists, a multiscale model of the formation of a 3D skin epithelium was established with TGF-beta 1 literature-derived rule sets and equations embedded within it. At the cellular level, an agent-based bottom-up model that focuses on individual interacting units ( keratinocytes) was used. This was based on literature-derived rules governing keratinocyte behavior and keratinocyte/ECM interactions. The selection of these rule sets is described in detail in this paper. The agent-based model was then linked with a subcellular model of TGF-beta 1 production and its action on keratinocytes simulated with a complex pathway simulator. This multiscale model can be run at a cellular level only or at a combined cellular/subcellular level. It was then initially challenged ( by wounding) to investigate the behavior of keratinocytes in wound healing at the cellular level. To investigate the possible actions of TGF-beta 1, several hypotheses were then explored by deliberately manipulating some of these rule sets at subcellular levels. This exercise readily eliminated some hypotheses and identified a sequence of spatial-temporal actions of TGF-beta 1 for normal successful wound healing in an easy-to-follow 3D model. We suggest this multiscale model offers a valuable, easy-to-visualize aid to our understanding of the actions of this key regulator in wound healing, and provides a model that can now be used to explore pathologies of wound healing
Evidence for genetic variance in resistance to tuberculosis in Great Britain and Irish Holstein-Friesian populations
peer-reviewedBackground: Here, we jointly summarise scientific evidence for genetic variation in resistance to infection with Mycobacterium bovis, the primary agent of bovine tuberculosis (TB), provided by two recent and separate studies of Holstein-Friesian dairy cow populations in Great Britain (GB) and Ireland. Methods: The studies quantified genetic variation within archived data from field and abattoir surveillance control programmes within each country. These data included results from the single intradermal comparative tuberculin test (SICTT), abattoir inspection for TB lesions and laboratory confirmation of disease status. Threshold animal models were used to estimate variance components for responsiveness to the SICTT and abattoir confirmed M. bovis infection. The link functions between the observed 0/1 scale and the liability scale were the complementary log-log in the GB, and logit link function in the Irish population. Results and discussion: The estimated heritability of susceptibility to TB, as judged by responsiveness to the SICTT, was 0.16 (0.012) and 0.14 (0.025) in the GB and Irish populations, respectively. For abattoir or laboratory confirmation of infection, estimates were 0.18 (0.044) and 0.18 (0.041) from the GB and the Irish populations, respectively. Conclusions: Estimates were all significantly different from zero and indicate that exploitable variation exists among GB and Irish Holstein Friesian dairy cows for resistance to TB. Epidemiological analysis suggests that factors such as variation in exposure or imperfect sensitivity and specificity would have resulted in underestimation of the true values
Clustered Coding Variants in the Glutamate Receptor Complexes of Individuals with Schizophrenia and Bipolar Disorder
Current models of schizophrenia and bipolar disorder implicate multiple genes,
however their biological relationships remain elusive. To test the genetic role
of glutamate receptors and their interacting scaffold proteins, the exons of ten
glutamatergic âhubâ genes in 1304 individuals were re-sequenced in
case and control samples. No significant difference in the overall number of
non-synonymous single nucleotide polymorphisms (nsSNPs) was observed between
cases and controls. However, cluster analysis of nsSNPs identified two exons
encoding the cysteine-rich domain and first transmembrane helix of GRM1 as a
risk locus with five mutations highly enriched within these domains. A new
splice variant lacking the transmembrane GPCR domain of GRM1 was discovered in
the human brain and the GRM1 mutation cluster could perturb the regulation of
this variant. The predicted effect on individuals harbouring multiple mutations
distributed in their ten hub genes was also examined. Diseased individuals
possessed an increased load of deleteriousness from multiple concurrent rare and
common coding variants. Together, these data suggest a disease model in which
the interplay of compound genetic coding variants, distributed among glutamate
receptors and their interacting proteins, contribute to the pathogenesis of
schizophrenia and bipolar disorders
A chemical survey of exoplanets with ARIEL
Thousands of exoplanets have now been discovered with a huge range of masses, sizes and orbits: from rocky Earth-like planets to large gas giants grazing the surface of their host star. However, the essential nature of these exoplanets remains largely mysterious: there is no known, discernible pattern linking the presence, size, or orbital parameters of a planet to the nature of its parent star. We have little idea whether the chemistry of a planet is linked to its formation environment, or whether the type of host star drives the physics and chemistry of the planetâs birth, and evolution. ARIEL was conceived to observe a large number (~1000) of transiting planets for statistical understanding, including gas giants, Neptunes, super-Earths and Earth-size planets around a range of host star types using transit spectroscopy in the 1.25â7.8 ÎŒm spectral range and multiple narrow-band photometry in the optical. ARIEL will focus on warm and hot planets to take advantage of their well-mixed atmospheres which should show minimal condensation and sequestration of high-Z materials compared to their colder Solar System siblings. Said warm and hot atmospheres are expected to be more representative of the planetary bulk composition. Observations of these warm/hot exoplanets, and in particular of their elemental composition (especially C, O, N, S, Si), will allow the understanding of the early stages of planetary and atmospheric formation during the nebular phase and the following few million years. ARIEL will thus provide a representative picture of the chemical nature of the exoplanets and relate this directly to the type and chemical environment of the host star. ARIEL is designed as a dedicated survey mission for combined-light spectroscopy, capable of observing a large and well-defined planet sample within its 4-year mission lifetime. Transit, eclipse and phase-curve spectroscopy methods, whereby the signal from the star and planet are differentiated using knowledge of the planetary ephemerides, allow us to measure atmospheric signals from the planet at levels of 10â100 part per million (ppm) relative to the star and, given the bright nature of targets, also allows more sophisticated techniques, such as eclipse mapping, to give a deeper insight into the nature of the atmosphere. These types of observations require a stable payload and satellite platform with broad, instantaneous wavelength coverage to detect many molecular species, probe the thermal structure, identify clouds and monitor the stellar activity. The wavelength range proposed covers all the expected major atmospheric gases from e.g. H2O, CO2, CH4 NH3, HCN, H2S through to the more exotic metallic compounds, such as TiO, VO, and condensed species. Simulations of ARIEL performance in conducting exoplanet surveys have been performed â using conservative estimates of mission performance and a full model of all significant noise sources in the measurement â using a list of potential ARIEL targets that incorporates the latest available exoplanet statistics. The conclusion at the end of the Phase A study, is that ARIEL â in line with the stated mission objectives â will be able to observe about 1000 exoplanets depending on the details of the adopted survey strategy, thus confirming the feasibility of the main science objectives.Peer reviewedFinal Published versio