ORCID Profile
0000-0003-1469-8748
Current Organisation
University of Tasmania
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Publisher: CSIRO Publishing
Date: 2017
DOI: 10.1071/AN16492
Abstract: A priori knowledge of seasonal pasture growth rates helps livestock farmers plan with pasture supply and feed budgeting. Longer forecasts may allow managers more lead time, yet inaccurate forecasts could lead to counterproductive decisions and foregone income. By using climate forecasts generated from historical archives or the global circulation model (GCM) called the Predictive Ocean Atmosphere Model for Australia (POAMA), we simulated pasture growth rates in a whole-farm model and compared growth-rate forecasts with growth-rate hindcasts (viz. retrospective forecasts). Hindcast pasture growth rates were generated using posterior weather data measured at two sites in north-western Tasmania, Australia. Forecasts were made on a monthly basis for durations of 30, 60 and 90 days. Across sites, forecasting approaches and durations, there were no significant differences between simulated growth-rate forecasts and hindcasts when our statistical inference was conducted using either the Kolmogorov–Smirnov statistic or empirical cumulative distribution functions. However, given that both of these tests were calculated by comparing growth-rate hindcasts with monthly distributions of forecasts, we also examined linear correlations between monthly hindcast values and median monthly growth-rate forecasts. Using this approach, we found a higher correlation between hindcasts and median monthly forecasts for 30 days than for 60 or 90 days, suggesting that monthly growth-rate forecasts provide more skilful predictions than forecast durations of 2 or 3 months. The range in monthly growth-rate forecasts at 30 days was less than that at 60 or 90 days, further reinfocing the aforementioned result. The strength of the correlation between growth-rate hindcasts and median monthly forecasts from the historical approach was similar to that generated using POAMA data. Overall, the present study found that (1) statistical methods of comparing forecast data with hindcast data are important, particularly if the former is a distribution whereas the latter is a single value, (2) 1-month growth-rate forecasts have less uncertainty than forecast durations of 2 or 3 months, and (3) there is little difference between pasture growth rates simulated using climate data from either historical records or from GCMs. To test the generality of these conclusions, the study should be extended to other dairy regions. Including more regions would both enable studies of sites with greater intra-seasonal climate variability, but also better highlight the impact of seasonal and regional variation in forecast skill of POAMA as applied in our forecasting methods.
Publisher: CSIRO Publishing
Date: 2018
DOI: 10.1071/AN16286
Abstract: Every year since 1990, the Australian Federal Government has estimated national greenhouse-gas (GHG) emissions to meet Australia’s reporting commitments under the United National Framework Convention on Climate Change (UNFCCC). The National Greenhouse Gas Inventory (NGGI) methodology used to estimate Australia’s GHG emissions has altered over time, as new research data have been used to improve the inventory emission factors and algorithms, with the latest change occurring in 2015 for the 2013 reporting year. As measuring the GHG emissions on farm is expensive and time-consuming, the dairy industry is reliant on estimating emissions using tools such as the Australian Dairy Carbon Calculator (ADCC). The present study compared the emission profiles of 41 Australian dairy farms with ADCC using the old (pre-2015) and new (post-2015) NGGI methodologies to examine the impact of the changes on the emission intensity across a range of dairy-farm systems. The estimated mean (±s.d.) GHG emission intensity increased by 3.0%, to 1.07 (±0.02) kg of carbon dioxide equivalents per kilogram of fat-and-protein-corrected milk (kg CO2e/kg FPCM). When comparing the emission intensity between the old and new NGGI methodologies at a regional level, the change in emission intensity varied between a 4.6% decrease and 10.4% increase, depending on the region. When comparing the source of emissions between old and new NGGI methodologies across the whole dataset, methane emissions from enteric fermentation and waste management both increased, while nitrous oxide emissions from waste management and nitrogen fertiliser management, CO2 emissions from energy consumption and pre-farm gate (supplementary feed and fertilisers) emissions all declined. Enteric methane remains a high source of emissions and so will remain a focus for mitigation research. However, these changes to the NGGI methodology have highlighted a new ‘hotspot’ in methane from manure management. Researchers and farm managers will have greater need to identify and implement practices on-farm to reduce methane losses to the environment.
Publisher: CSIRO Publishing
Date: 2016
DOI: 10.1071/AN15296
Abstract: Milking cows typically dominate dairy farm greenhouse gas (GHG) emissions, but replacement heifers also contribute to farm emissions and can increase the emission intensity of milk production. In northern Australia, heifers generally graze poorer-quality subtropical pastures and in the absence of energy-dense supplementary feed during periods of low pasture growth, liveweight (LW) gain can be restricted. This modelling study examined the time required and enteric methane (CH4) emissions produced in raising dairy heifers to a target LW for first mating by feeding a diet assuming either constant (static) or variable (dynamic) nutritive values. Using a static approach (Australian Feeding Standards methodology), and assuming a target mating LW of 360 kg, growing heifers reached their target LW at ~18 months of age while consuming C4 grasses with a constant metabolisable energy content of 9.5 MJ/kg dry matter (DM) or 11 months of age on a diet of 11.0 MJ/kg DM. Enteric CH4 emissions were 1.2 and 0.8 t of carbon dioxide equivalents/heifer over the 18- and 11-month periods, respectively. To explore the extent with which climatic conditions influence seasonal pasture availability and nutritive value with a dynamic approach, we used a whole-farm biophysical model (SGS pasture model) to simulate diets with mean metabolisable energy values of 9.5 and 10.9 MJ/ kg DM. On average (±s.d.), heifers required 22 ± 4 and 17 ± 1 months, respectively, to reach target LW, with cumulative enteric CH4 emissions of 1.22 ± 0.20 and 0.72 ± 0.04 t carbon dioxide equivalents, respectively. The dynamic approach resulted in slower LW gain due to the variable nutritive value of the diet throughout the year, resulting in seasonal periods of LW plateauing or decline. Maintaining heifers on high-quality diets in subtropical northern Australia should result in increased daily LW gain, lower enteric CH4 emissions to mating LW and earlier calving. Together, these factors reduce their lifetime emission intensity of milk production.
Publisher: CSIRO Publishing
Date: 2009
DOI: 10.1071/CP08446
Abstract: In the cool temperate dairy regions of Tasmania, there is heavy reliance on irrigation to maximise pasture performance by ensuring that plants do not suffer water stress. Consequently, irrigation water has often been applied at a greater amount than plant water requirements, resulting in low efficiencies. An irrigation experiment was undertaken in north-western Tasmania between October 2007 and April 2008, examining the effect of deficit irrigation treatments on pasture growth and water-use efficiency. A rainfall deficit (potential evapotranspiration minus rainfall) of 20 mm was implemented to schedule irrigation, at which point 20, 16, 12, 8, or 0 mm of irrigation water was applied, referred to as treatments I100%, I80%, I60%, I40%, and I0%, respectively. The trial was a randomised complete block design with 4 replications. There were 21 irrigation events between October and April. The experimental area was grazed by 60 Holstein Friesian heifers at a grazing interval coinciding with emergence of 2.5–3.0 new ryegrass leaves/tiller of the I100% treatment. Cumulative pasture consumption for the irrigated period was 9.2, 8.9, 7.6, 6.9, and 3.7 t dry matter (DM)/ha for the I100%, I80%, I60%, I40%, and I0% treatments, respectively. The resulting marginal irrigation water-use index (MIWUI marginal production due to irrigation) was 1.29, 1.54, 1.55, and 1.87 t DM/ML, for the I100%, I80%, I60%, and I40% treatments, respectively. The results of this study were modelled using the biophysical model DairyMod, with strong agreement between observed and modelled data. DairyMod was then used to simulate the MIWUI for 5 differing dairy regions of Tasmania using 40 years of climatic data (1968–2007) under 3 differing nitrogen management strategies by the 5 irrigation treatments. The modelling indicated that a MIWUI greater than 2 t DM/ML can be achieved in all regions. The current study has shown that the opportunity exists for irrigated pastoral systems to better manage an increasingly scarce resource and substantially improve responses to irrigation.
Publisher: CSIRO Publishing
Date: 2012
DOI: 10.1071/AN12061
Abstract: The Australian dairy industry contributes ~1.6% of the nation’s greenhouse gas (GHG) emissions, emitting an estimated 9.3 million tonnes of carbon dioxide equivalents (CO2e) per annum. This study examined 41 contrasting Australian dairy farms for their GHG emissions using the Dairy Greenhouse Gas Abatement Strategies calculator, which incorporates Intergovernmental Panel on Climate Change and Australian inventory methodologies, algorithms and emission factors. Sources of GHG emissions included were pre-farm embedded emissions associated with key farm inputs (i.e. grains and concentrates, forages and fertilisers), CO2 emissions from electricity and fuel consumption, methane emissions from enteric fermentation and animal waste management, and nitrous oxide emissions from animal waste management and nitrogen fertilisers. The estimated mean (±s.d.) GHG emissions intensity was 1.04 ± 0.17 kg CO2 equivalents/kg of fat and protein-corrected milk (kg CO2e/kg FPCM). Enteric methane emissions were found to be approximately half of total farm emissions. Linear regression analysis showed that 95% of the variation in total farm GHG emissions could be explained by annual milk production. While the results of this study suggest that milk production alone could be a suitable surrogate for estimating GHG emissions for national inventory purposes, the GHG emissions intensity of milk production, on an in idual farm basis, was shown to vary by over 100% (0.76–1.68 kg CO2e/kg FPCM). It is clear that using a single emissions factor, such as milk production alone, to estimate any given in idual farm’s GHG emissions, has the potential to either substantially under- or overestimate in idual farms’ GHG emissions.
Publisher: Springer Science and Business Media LLC
Date: 02-05-2023
DOI: 10.1007/S11625-023-01323-2
Abstract: While society increasingly demands emissions abatement from the livestock sector, farmers are concurrently being forced to adapt to an existential climate crisis. Here, we examine how stacking together multiple systems adaptations impacts on the productivity, profitability and greenhouse gas (GHG) emissions of livestock production systems under future climates underpinned by more frequent extreme weather events. Without adaptation, we reveal that soil carbon sequestration (SCS) in 2050 declined by 45–133%, heralding dire ramifications for CO 2 removal aspirations associated with SCS in nationally determined contributions. Across adaptation-mitigation bundles examined, mitigation afforded by SCS from deep-rooted legumes was lowest, followed by mitigation from status quo SCS and woody vegetation, and with the greatest mitigation afforded by adoption of enteric methane inhibitor vaccines. Our results (1) underline a compelling need for innovative, disruptive technologies that dissect the strong, positive coupling between productivity and GHG emissions, (2) enable maintenance or additional sequestration of carbon in vegetation and soils under the hotter and drier conditions expected in future, and (3) illustrate the importance of holistically assessing systems to account for pollution swapping, where mitigation of one type of GHG (e.g., enteric methane) can result in increased emissions of another (e.g., CO 2 ). We conclude that transdisciplinary participatory modelling with stakeholders and appropriate bundling of multiple complementary adaptation-mitigation options can simultaneously benefit production, profit, net emissions and emissions intensity.
Publisher: American Chemical Society (ACS)
Date: 02-09-2022
Publisher: CSIRO Publishing
Date: 2014
DOI: 10.1071/AN14421
Abstract: Livestock greenhouse gas (GHG) emissions form the largest proportion of emissions from agriculture. Here we seek intervention strategies for sustainably intensifying the productivity of prime lamb enterprises without increasing net farm emissions. We apply a biophysical model and an emissions calculator to determine the implications of several interventions to a prime lamb farm in south-eastern Australia. We examine the effects of lamb liveweight or age at sale, weaning rate, maiden ewe joining age, genetic feed-use efficiency, supplementary grain feeding according to green pasture availability, soil fertility and botanical composition. For each intervention, stocking rates were optimised to the lesser of a minimum ground cover threshold or a maximum supplementary grain feeding threshold. Total animal production of the baseline farm was 478 kg clean fleece weight plus liveweight (CFW+LWT)/ha.annum and ranged from 166 to 609 kg CFW+LWT/ha.annum for interventions that replaced existing pastures with annual ryegrass or increased soil fertility respectively. Annual GHG emissions intensity of the baseline farm was 8.7 kg CO2-e/kg CFW+LWT and varied between 7.7 and 9.2 kg CO2-e/kg CFW+LWT for interventions that reduced maiden ewe joining age or increased sale liveweight, respectively. Stocking rate primarily governed total animal production, and in many cases production drove emissions, so interventions that increased production did not always reduce emissions intensity. Indeed, replacing existing perennial ryegrass/subterranean clover mixed pastures with perennial legume swards caused large reductions in both production and emissions, and interventions that increased soil fertility via phosphate addition caused large increases in production and emissions as a consequence, both strategies had little effect on emissions intensity. Implementing several beneficial interventions simultaneously further increased production and reduced emissions intensity relative to implementing in idual interventions alone. Baseline production increased by 61% by increasing soil fertility, improving feed-use efficiency and reducing the joining age of maiden ewes, while baseline emissions intensity was reduced by 17% by improving feed use efficiency, reducing the joining age of maiden ewes and supplementary grain feeding. We demonstrate that imposing several strategies on existing sheep farming systems simultaneously is more conducive to sustainable agricultural intensification than is imposing any single intervention alone, provided in idual strategies were beneficial in their own right. The best strategies for both sustainably increasing production and reducing emissions intensity are those that decouple the linkage between production and emissions such as interventions that shift the balance of the flock away from adults and towards juveniles while holding average annual stocking rates constant.
Publisher: CSIRO Publishing
Date: 2018
DOI: 10.1071/AN15632
Abstract: Recognition is increasingly given to the need of improving agricultural production and efficiency to meet growing global food demand, while minimising environmental impacts. Livestock forms an important component of global food production and is a significant contributor to anthropogenic greenhouse-gas (GHG) emissions. As such, livestock production systems (LPS) are coming under increasing pressure to lower their emissions. In developed countries, LPS have been gradually reducing their emissions per unit of product (emissions intensity EI) over time through improvements in production efficiency. However, the global challenge of reducing net emissions (NE) from livestock requires that the rate of decline in EI surpasses the productivity increases required to satisfy global food demand. Mechanistic and dynamic whole farm-system models can be used to estimate farm-gate GHG emissions and to quantify the likely changes in farm NE, EI, farm productivity and farm profitability as a result of applying various mitigation strategies. Such models are also used to understand the complex interactions at the farm-system level and to account for how component mitigation strategies perform within the complexity of these interactions, which is often overlooked when GHG mitigation research is performed only at the component level. The results of such analyses can be used in extension activities and to encourage adoption, increase awareness and in assisting policy makers. The present paper reviews how whole farm-system modelling has been used to assess GHG mitigation strategies, and the importance of understanding metrics and allocation approaches when assessing GHG emissions from LPS.
Publisher: Wiley
Date: 21-12-2021
DOI: 10.1111/AJR.12807
Abstract: The objective of this study was to determine the impact of a new salaried medical officer position on health service provision and organisational performance. Health service staff were invited to complete a survey to ascertain their overall satisfaction with the salaried medical officer position and impact on their workflow. Purposive s ling identified respondents for interviews to further explore the experiences of health service staff. Financial, administrative and quality information was extracted for analysis. Medium size rural health service in Victoria, Australia. All general practitioner, nursing and allied health staff employed by, or who provide services to, the health service. Satisfaction with the salaried medical officer position, ability to address patient concerns, themes from interviews, organisational performance data. Forty surveys (general practitioner, nursing and allied health) were returned and 10 interviews completed. The mean rating for satisfaction with the salaried medical officer position was 8.4 out of 10. Addressing patient care concerns was rated significantly easier by nursing and allied health staff when the salaried medical officer was working. The interviews identified three broad themes: improved efficiency, increased accessibility and eliminated service gaps. Health service staff reported that a salaried medical officer position at a rural health service improved work efficiency, increased accessibility to timely medical advice and improved quality of care, particularly patients at risk of sudden deterioration.
Publisher: CSIRO Publishing
Date: 2014
DOI: 10.1071/CP13408
Abstract: Potential exists to select pasture species better adapted to anticipated warmer temperatures and lower rainfall, associated with increasing atmospheric carbon dioxide (CO2) and other greenhouse gas concentrations, to maximise pasture yields and persistence. This study assessed the effect of increasing three plant traits in perennial ryegrass (Lolium perenne L.) to adapt to future climates: root depth heat tolerance, defined as the ability of plant to grow at high temperatures and responsiveness to elevated CO2 concentrations. Pasture production was simulated using the Sustainable Grazing Systems Pasture model at three sites with temperate climates in south-eastern Australia: Hamilton, Victoria (medium rainfall) Ellinbank, Victoria (high rainfall) and Elliott, Tasmania (high rainfall). Two future climate scenarios were created at each site by scaling the historical climate (1971–2010) by +1°C with –10% rain (435 ppm CO2) and +2°C with –20% rain (535 ppm CO2). A genotype × environment interaction suggested that the plants traits most effective at increasing pasture yield differed depending on the local climate. Increased root depth was the most effective change in a single trait that increased pasture harvested at Elliott, increased heat tolerance was most effective at Ellinbank, whereas increasing all three in idual traits was similarly effective at Hamilton. At each site, the most effective traits increased pasture growth during the period between late spring and mid-summer compared with the current cultivar. When all three traits were increased at the same time, the pasture production advantage was greater than the additive effects of changing single traits at Hamilton and Ellinbank. Further consideration of the feasibility of selecting multiple traits and the effects of a broader range of climate projections is required. Nonetheless, results of this study provide guidance to plant breeders for selection of traits adapted to future climates.
Publisher: Research Square Platform LLC
Date: 02-06-2023
DOI: 10.21203/RS.3.RS-2939816/V1
Abstract: Land managers are challenged with balancing priorities for agri-food production, greenhouse gas (GHG) abatement, natural conservation, social and economic license to operate. We co-designed pathways for transitioning farming systems to net-zero emissions under future climates. Few interventions enhanced productivity and profitability while also reducing GHG emissions. Seaweed ( Asparagopsis ) feed supplement and planting trees enabled the greatest mitigation (67–95%), while enterprise ersification (installation of wind turbines) and improved feed-conversion efficiency (FCE) were most conducive to improved profitability (17–39%). Mitigation efficacy was h ered by adoptability. Serendiptiously, the least socially acceptable option – business as usual and purchasing carbon credits to offset emissions – were also the most costly options. In contrast, stacking synergistic interventions enabling enteric methane mitigation, improved FCE and carbon removals entirely negated net emissions in a profitable way. We conclude that costs of transitioning to net-zero vary widely (-64% to + 30%), depending on whether interventions are stacked and/or elicit productivity co-benefits.
Publisher: Elsevier BV
Date: 06-2021
Publisher: Wiley
Date: 29-08-2021
DOI: 10.1111/GCB.15816
Abstract: Livestock have long been integral to food production systems, often not by choice but by need. While our knowledge of livestock greenhouse gas (GHG) emissions mitigation has evolved, the prevailing focus has been—somewhat myopically—on technology applications associated with mitigation. Here, we (1) examine the global distribution of livestock GHG emissions, (2) explore social, economic and environmental co‐benefits and trade‐offs associated with mitigation interventions and (3) critique approaches for quantifying GHG emissions. This review uncovered many insights. First, while GHG emissions from ruminant livestock are greatest in low‐ and middle‐income countries (LMIC globally, 66% of emissions are produced by Latin America and the Caribbean, East and southeast Asia and south Asia), the majority of mitigation strategies are designed for developed countries. This serious concern is heightened by the fact that 80% of growth in global meat production over the next decade will occur in LMIC. Second, few studies concurrently assess social, economic and environmental aspects of mitigation. Of the 54 interventions reviewed, only 16 had triple‐bottom line benefit with medium–high mitigation potential. Third, while efforts designed to stimulate the adoption of strategies allowing both emissions reduction (ER) and carbon sequestration (CS) would achieve the greatest net emissions mitigation, CS measures have greater potential mitigation and co‐benefits. The scientific community must shift attention away from the prevailing myopic lens on carbon, towards more holistic, systems‐based, multi‐metric approaches that carefully consider the raison d'être for livestock systems. Consequential life cycle assessments and systems‐aligned ‘socio‐economic planetary boundaries’ offer useful starting points that may uncover leverage points and cross‐scale emergent properties. The derivation of harmonized, globally reconciled sustainability metrics requires iterative dialogue between stakeholders at all levels. Greater emphasis on the simultaneous characterization of multiple sustainability dimensions would help avoid situations where progress made in one area causes maladaptive outcomes in other areas.
Publisher: CSIRO Publishing
Date: 2014
DOI: 10.1071/AN14436
Abstract: Ruminant livestock are generally considered inefficient converters of dietary nitrogen (N) into animal product. Animal nitrogen use efficiency (NUE) is a measure of the relative transformation of feed N into product and in dairy systems this is often expressed as milk N per unit of N intake (g milk N/100 g N intake). This study was a theoretical exercise to explore the relative potential efficacy and value proposition of breeding versus feeding to improve NUE, reduce urinary N excretion and associated environmental impact in pasture-based dairy systems. The biophysical whole farm systems model DairyMod was used across three dairying regions of south-eastern Australia representing a high-rainfall cool temperate climate (HRCT), a high-rainfall temperate climate (HRT) and a medium-rainfall temperate climate (MRT) to examine the two theoretical approaches of (1) maintaining the same amount of N exported in milk from a reduced N intake and (2) increasing the amount of N exported in milk for the same amount of dietary N intake. Sixteen scenarios were explored for each site these include four supplementary feed N (SN) concentrations (ranging from 1% to 4% N) combined with four milk N (MN) concentrations (ranging from 0.50% to 0.65% N). Reducing the SN concentration from 4% to 1% increased the 30-year mean model-predicted NUEs from ~16 g milk N/100 g N intake at all three sites to between 23 and 28 g milk N/100 g N intake, with the least and greatest improvements in NUE occurring for the HRCT and MRT sites, respectively. Corresponding to this improved NUE through reduced SN concentrations, model-predicted N2O emissions declined from 3.0 to 1.3 t carbon dioxide equivalents (CO2-e)/ha.annum for the HRCT site, from 4.2 to 2.1 t CO2-e/ha.annum for the HRT site and from 4.4 to 2.1 t CO2-e/ha.annum for the MRT site, representing a decline of between 50% and 57%. In contrast, increasing the MN concentration from 0.50% to 0.65% increased the 30-year mean model-predicted NUEs from 17 to 22 g milk N/100 g N intake for the HRCT site, from 18 to 23 g milk N/100 g N intake for the HRT site and from 18 to 24 g milk N/100 g N intake for the MRT site. Corresponding to the improved NUE through increased MN concentrations, model-predicted N2O emissions declined from 2.3 to 2.0 t CO2-e/ha.annum for the HRCT site, from 3.3 to 3.1 t CO2-e/ha.annum for the HRT site and from 3.4 to 3.2 t CO2-e/ha.annum for the MRT site representing a decline of between 7% and 11%. These results suggest that improving animal NUE to reduce associated N2O losses holds much more promise if achieved through a reduction in the amount of N in supplementary feed than through increasing N exported in milk. This is an important finding for the Australian dairy industry, since manipulation of dietary N to better balance the energy to protein ratio would be much easier to implement than manipulation of N concentration in milk through genetics.
Publisher: CSIRO Publishing
Date: 2019
DOI: 10.1071/CP18566
Abstract: The nitrogen (N) nutrition of dairy pasture systems in southern Australia has changed from almost total dependence on legumes in the early 1990s through to almost complete reliance on N fertiliser today. Although some tactical N fertiliser is applied to sheep and beef pastures to boost late winter growth, most N fertiliser usage on pastures remains with the dairy industry. Intensification of the farming system, through increased stocking rates and a greater reliance on N fertiliser, has increased N loading, leading to higher potential N losses through volatilisation, leaching and denitrification. With increasing focus on the environmental impact of livestock production, reducing N loading on dairy farms will become increasingly important to the longer-term sustainability of the dairy industry, possibly with the expectation that Australia will join most of the developed countries in regulating N loading in catchments. This paper examines N usage in modern pasture-based dairy systems, the N cycle and loss pathways, and summarises a series of recent modelling studies and component research, investigating options for improving N use efficiency (NUE) and reducing whole-farm N balance. These studies demonstrate that the application of revised practices has the potential to improve NUE, with increasing sophistication of precision technologies playing an important role. This paper discusses the challenge of sustainably intensifying grazing systems with regard to N loading and what approaches exist now or have the potential to decouple the link between production, fertiliser use and environmental impact.
Publisher: Elsevier BV
Date: 10-2018
Publisher: Elsevier BV
Date: 05-2021
Publisher: Elsevier BV
Date: 06-2011
Publisher: Elsevier BV
Date: 09-2018
Publisher: CSIRO Publishing
Date: 2014
Publisher: MDPI AG
Date: 18-10-2020
DOI: 10.3390/IJMS21207705
Abstract: The COL7A1 gene encodes homotrimer fibrils essential for anchoring dermal and epidermal layers, and pathogenic mutations in COL7A1 can cause recessive or dominant dystrophic epidermolysis bullosa. As a monogenic disease gene, COL7A1 constitutes a potential target for antisense oligomer-mediated exon skipping, a therapy applicable to a growing number of other genetic disorders. However, certain characteristics of COL7A1: many exons, low average intron size, and repetitive and guanine-cytosine rich coding sequence, present challenges to the design of specific and effective antisense oligomers. While targeting COL7A1 exons 10 and 73 for excision from the mature mRNA, we discovered that antisense oligomers comprised of 2′-O-methyl modified bases on a phosphorothioate backbone and phosphorodiamidate morpholino oligomers produced similar, but distinctive, splicing patterns including excision of adjacent nontargeted exons and/or retention of nearby introns in some transcripts. We found that the nonsequential splicing of certain introns may alter pre-mRNA processing during antisense oligomer-mediated exon skipping and, therefore, additional studies are required to determine if the order of intron removal influences multiexon skipping and/or intron retention in processing of the COL7A1 pre-mRNA.
Publisher: Elsevier BV
Date: 06-2020
No related grants have been discovered for Karen Christie-Whitehead.