78 research outputs found
Mitochondrial Haplotypes suggest Genetic Component for Habitat Preference in Blue Crabs
Atlantic blue crabs (Callinectes sapidus) are ecologically and commercially fundamental. Life stages are punctuated with migration. Adults and juveniles live in estuaries and sounds. Larval stages develop in the coastal ocean. Juvenile and adult crabs occupy habitats from high salinities to fresh water. We determined whether maturing juvenile and adult blue crab habitat use is reflected in mitochondrial cytochrome oxidase 1 haplotypes. High salinity crabs had lower haplotype diversity (0.7260 ± .03900) compared to spawning crabs (0.9841 ± .00021) and low salinity crabs (0.94154 ± .00118). Significant pairwise differences in haplotypes were found between high salinity and spawning crabs (Nm = 0.26018, p < 0.001), and between high salinity and low salinity crabs (Nm = 0.19482, p < 0.001) indicating a lack of gene flow. Crabs from high salinity had highly significant genetic differentiation compared to spawning crabs (Fst = 0.11830, p < 0.001) and low salinity crabs (Fst = 0.09689, p < 0.001). Results support the hypothesis that genetics influence habitat selection. Crab larvae mix in the coastal ocean but occupy specific habitats upon return to sounds and estuaries. These findings have implications for the management of fisheries
Optimising commercial traits through gene editing in aquaculture: Strategies for accelerating genetic improvement
Aquaculture is one of the fastest-growing food production sectors. As the global human population continues to increase and further pressure is added to the prospects of achieving global food security, aquaculture is expected to play an integral role in meeting future nutrition demands. With advances in genetic technologies over recent years, much progress has been made within the realm of selective breeding. Despite success, selective breeding programs have limitations to the rate of genetic gain they can achieve. The incorporation of targeted genetic technologies, such as gene editing, into research related to selective breeding programs will help identify specific genes related to commercially desirable traits, as well as expedite genetic improvement. This review summarises research encompassing the most commonly targeted traits using gene editing within aquaculture, namely reproduction and development, pigmentation, growth and disease resistance. In addition, this review illustrates how the incorporation of gene editing can expedite genetic improvement through the rapid fixation of desirable alleles, as well as suggests strategies to accelerate genetic improvement for aquaculture production
Improving Distances to Binary Millisecond Pulsars with Gaia
Pulsar distances are notoriously difficult to measure, and play an important
role in many fundamental physics experiments, such as pulsar timing arrays
(PTAs). Here we perform a cross-match between International PTA pulsars (IPTA)
and Gaia's DR2 and DR3. We then combine the IPTA pulsar's parallax with its
binary companion's parallax, found in Gaia, to improve the distance measurement
to the binary. We find 7 cross-matched IPTA pulsars in Gaia DR2, and when using
Gaia DR3, we find 6 IPTA pulsar cross-matches, but with 7 Gaia objects. Moving
from Gaia DR2 to Gaia DR3, we find that the Gaia parallaxes for the
successfully cross-matched pulsars improved by , and pulsar distances
improved by . Finally, we find that binary companions with a
detection are unreliable associations, setting a high bar for successful
cross-matches.Comment: 9 pages, 8 figures, 4 table
A novel μCT analysis reveals different responses of bioerosion and secondary accretion to environmental variability
Corals build reefs through accretion of calcium carbonate (CaCO3) skeletons, but net reef growth also depends on bioerosion by grazers and borers and on secondary calcification by crustose coralline algae and other calcifying invertebrates. However, traditional field methods for quantifying secondary accretion and bioerosion confound both processes, do not measure them on the same time-scale, or are restricted to 2D methods. In a prior study, we compared multiple environmental drivers of net erosion using pre- and post-deployment micro-computed tomography scans (μCT; calculated as the % change in volume of experimental CaCO3 blocks) and found a shift from net accretion to net erosion with increasing ocean acidity. Here, we present a novel μCT method and detail a procedure that aligns and digitally subtracts pre- and post-deployment μCT scans and measures the simultaneous response of secondary accretion and bioerosion on blocks exposed to the same environmental variation over the same time-scale. We tested our method on a dataset from a prior study and show that it can be used to uncover information previously unattainable using traditional methods. We demonstrated that secondary accretion and bioerosion are driven by different environmental parameters, bioerosion is more sensitive to ocean acidity than secondary accretion, and net erosion is driven more by changes in bioerosion than secondary accretion
Photochemically-produced SO in the atmosphere of WASP-39b
Photochemistry is a fundamental process of planetary atmospheres that
regulates the atmospheric composition and stability. However, no unambiguous
photochemical products have been detected in exoplanet atmospheres to date.
Recent observations from the JWST Transiting Exoplanet Early Release Science
Program found a spectral absorption feature at 4.05 m arising from SO
in the atmosphere of WASP-39b. WASP-39b is a 1.27-Jupiter-radii, Saturn-mass
(0.28 M) gas giant exoplanet orbiting a Sun-like star with an equilibrium
temperature of 1100 K. The most plausible way of generating SO in
such an atmosphere is through photochemical processes. Here we show that the
SO distribution computed by a suite of photochemical models robustly
explains the 4.05 m spectral feature identified by JWST transmission
observations with NIRSpec PRISM (2.7) and G395H (4.5). SO
is produced by successive oxidation of sulphur radicals freed when hydrogen
sulphide (HS) is destroyed. The sensitivity of the SO feature to the
enrichment of the atmosphere by heavy elements (metallicity) suggests that it
can be used as a tracer of atmospheric properties, with WASP-39b exhibiting an
inferred metallicity of 10 solar. We further point out that
SO also shows observable features at ultraviolet and thermal infrared
wavelengths not available from the existing observations.Comment: 39 pages, 14 figures, accepted to be published in Natur
Photochemically produced SO2 in the atmosphere of WASP-39b
Photochemistry is a fundamental process of planetary atmospheres that regulates the atmospheric composition and stability1. However, no unambiguous photochemical products have been detected in exoplanet atmospheres so far. Recent observations from the JWST Transiting Exoplanet Community Early Release Science Program2,3 found a spectral absorption feature at 4.05 μm arising from sulfur dioxide (SO2) in the atmosphere of WASP-39b. WASP-39b is a 1.27-Jupiter-radii, Saturn-mass (0.28 MJ) gas giant exoplanet orbiting a Sun-like star with an equilibrium temperature of around 1,100 K (ref. 4). The most plausible way of generating SO2 in such an atmosphere is through photochemical processes5,6. Here we show that the SO2 distribution computed by a suite of photochemical models robustly explains the 4.05-μm spectral feature identified by JWST transmission observations7 with NIRSpec PRISM (2.7σ)8 and G395H (4.5σ)9. SO2 is produced by successive oxidation of sulfur radicals freed when hydrogen sulfide (H2S) is destroyed. The sensitivity of the SO2 feature to the enrichment of the atmosphere by heavy elements (metallicity) suggests that it can be used as a tracer of atmospheric properties, with WASP-39b exhibiting an inferred metallicity of about 10× solar. We further point out that SO2 also shows observable features at ultraviolet and thermal infrared wavelengths not available from the existing observations
Early Release Science of the exoplanet WASP-39b with JWST NIRISS
Transmission spectroscopy provides insight into the atmospheric properties
and consequently the formation history, physics, and chemistry of transiting
exoplanets. However, obtaining precise inferences of atmospheric properties
from transmission spectra requires simultaneously measuring the strength and
shape of multiple spectral absorption features from a wide range of chemical
species. This has been challenging given the precision and wavelength coverage
of previous observatories. Here, we present the transmission spectrum of the
Saturn-mass exoplanet WASP-39b obtained using the SOSS mode of the NIRISS
instrument on the JWST. This spectrum spans m in wavelength and
reveals multiple water absorption bands, the potassium resonance doublet, as
well as signatures of clouds. The precision and broad wavelength coverage of
NIRISS-SOSS allows us to break model degeneracies between cloud properties and
the atmospheric composition of WASP-39b, favoring a heavy element enhancement
("metallicity") of the solar value, a sub-solar
carbon-to-oxygen (C/O) ratio, and a solar-to-super-solar potassium-to-oxygen
(K/O) ratio. The observations are best explained by wavelength-dependent,
non-gray clouds with inhomogeneous coverage of the planet's terminator.Comment: 48 pages, 12 figures, 2 tables. Under review at Natur
Early Release Science of the exoplanet WASP-39b with JWST NIRCam
Measuring the metallicity and carbon-to-oxygen (C/O) ratio in exoplanet
atmospheres is a fundamental step towards constraining the dominant chemical
processes at work and, if in equilibrium, revealing planet formation histories.
Transmission spectroscopy provides the necessary means by constraining the
abundances of oxygen- and carbon-bearing species; however, this requires broad
wavelength coverage, moderate spectral resolution, and high precision that,
together, are not achievable with previous observatories. Now that JWST has
commenced science operations, we are able to observe exoplanets at previously
uncharted wavelengths and spectral resolutions. Here we report time-series
observations of the transiting exoplanet WASP-39b using JWST's Near InfraRed
Camera (NIRCam). The long-wavelength spectroscopic and short-wavelength
photometric light curves span 2.0 - 4.0 m, exhibit minimal systematics,
and reveal well-defined molecular absorption features in the planet's spectrum.
Specifically, we detect gaseous HO in the atmosphere and place an upper
limit on the abundance of CH. The otherwise prominent CO feature at 2.8
m is largely masked by HO. The best-fit chemical equilibrium models
favour an atmospheric metallicity of 1-100 solar (i.e., an enrichment
of elements heavier than helium relative to the Sun) and a sub-stellar
carbon-to-oxygen (C/O) ratio. The inferred high metallicity and low C/O ratio
may indicate significant accretion of solid materials during planet formation
or disequilibrium processes in the upper atmosphere.Comment: 35 pages, 13 figures, 3 tables, Nature, accepte
GA4GH: International policies and standards for data sharing across genomic research and healthcare.
The Global Alliance for Genomics and Health (GA4GH) aims to accelerate biomedical advances by enabling the responsible sharing of clinical and genomic data through both harmonized data aggregation and federated approaches. The decreasing cost of genomic sequencing (along with other genome-wide molecular assays) and increasing evidence of its clinical utility will soon drive the generation of sequence data from tens of millions of humans, with increasing levels of diversity. In this perspective, we present the GA4GH strategies for addressing the major challenges of this data revolution. We describe the GA4GH organization, which is fueled by the development efforts of eight Work Streams and informed by the needs of 24 Driver Projects and other key stakeholders. We present the GA4GH suite of secure, interoperable technical standards and policy frameworks and review the current status of standards, their relevance to key domains of research and clinical care, and future plans of GA4GH. Broad international participation in building, adopting, and deploying GA4GH standards and frameworks will catalyze an unprecedented effort in data sharing that will be critical to advancing genomic medicine and ensuring that all populations can access its benefits
The James Webb Space Telescope Mission
Twenty-six years ago a small committee report, building on earlier studies,
expounded a compelling and poetic vision for the future of astronomy, calling
for an infrared-optimized space telescope with an aperture of at least .
With the support of their governments in the US, Europe, and Canada, 20,000
people realized that vision as the James Webb Space Telescope. A
generation of astronomers will celebrate their accomplishments for the life of
the mission, potentially as long as 20 years, and beyond. This report and the
scientific discoveries that follow are extended thank-you notes to the 20,000
team members. The telescope is working perfectly, with much better image
quality than expected. In this and accompanying papers, we give a brief
history, describe the observatory, outline its objectives and current observing
program, and discuss the inventions and people who made it possible. We cite
detailed reports on the design and the measured performance on orbit.Comment: Accepted by PASP for the special issue on The James Webb Space
Telescope Overview, 29 pages, 4 figure
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